Charlise,
Probably most of this has been mentioned by others, but I find myself with the time to type so rather than waste time reading what has already been said, I'll just type.
The answers to your questions is not exactly straight forward. Having a pool is like having a couple of dogs. There is a mess to clean up everyday. If you do this cleanup daily, you breeze through it in relatively short period of time. If you wait and do it once a week, then it takes considerably longer.
The first thing you need to know is how much water is in your pool. From this number all other considerations can be worked out. Pools are magnets for all sorts of organic material, leaves, bugs, bird droppings dust, dirt etc. The longer this stuff remains in the water the more it breaks down providing nutrients for algae and water creatures that think your pool is just a great AI to stay at.
Chemicals:
You can drive yourself nuts with a detailed water test kit, chasing numerical values up and down the scale rarely if ever getting all the values within the recommended zone at the same time. Pool water is affected by rain, oxygen levels, hard water added when replacing evaporated water etc. A simple test kit is a better place to start. The two most important levels to watch are chlorine level and the Ph of the water. Most pool shops will gladly sell you a water test kit that gives you easy readings for these two values for about $9 US. Get one.
The sun is not your pool's friend. Sunlight especially at the extreme UV intensity found here breaks down chlorine in water quite quickly. New chlorine needs to be added continuously to keep the levels within the normal range as indicated by your test kit. If chlorine levels drop too much and remain low for too long, algae and bacteria begin to take hold. Left uncorrected, you'll have a pool full of thick sludge in just a few days. Mucho work, time, extra chemicals and electricity will be required to correct this, so try not to get here.
After you add new water to top up the water level (a lot of water will evaporate from your pool over the course of a few sunny days) or after a significant rain, you will probably have to add acid to your pool to drop the Ph to levels that allow the chlorine to work effectively. Your test kit will tell you what to add and when.
I add an algacide to my pool once a week to help prevent the start of an algae bloom. Relatively cheap and a gallon lasts maybe a month (depending on pool size). Algacide alone will not prevent an algae bloom if you take off for a week and no one adds chlorine to your pool. It does slow down the algae's ability to colonize your pool quickly during those short term periods when the chlorine level is lower than it should be. We can talk about water polishers, shocking the pool and flocculants at another time if you wish.
Cleaning:
The cleaner you keep your water the less time and chemicals you have to devote to the overall effort. At home, pools are normally not used in the winter and temperatures prevent algae growth so no maintenance is required and obviously no chemicals either during those months when the pool is frozen solid. Here in the DR there is no such maintenance respite so chemicals and effort are required year round. The more you swim in the pool the more organic materials (skin cells) and yucky chemicals (sunscreen, urine, hair spray, deodorant etc) get in and thus need to be removed/neutralized continuously. If you provide food for critters, algae, bacteria and a water environment conducive to their longevity, then you *will* have critters and an ongoing war with them.
The long and short of all this, a pool requires imho daily maintenance. See above. The 30 minutes I spend each day making sure everything is clean and checking chemicals is time well spent so I do not have to run pumps/filters continuously and use lots of extra chemicals later on to clean up a mess that has gotten out of hand. If you are not prepared to actively and regularly work on your pool, don't get one. If you are away more than you are at home, don't get a pool - you'll have to pay someone to look after it. Algae and water acidity imbalances will damage the paint or the liner in your pool. If someone is only dealing with the pool once a week, there are potentially six days that an imbalance can be doing a little bit of damage, spread out month after month, that nice blue pool, will look dull and green no mater how clean the water is as the pool itself is no longer azul.
Oxygen:
There are two types of bacteria. Aerobic and Anaerobic. Those that live in oxygen rich environments and those that live in environments without a lot of oxygen. Generally, the anaerobic kind cause disease and make people sick. Not always but generally. It is therefore important that your pool water gets enough oxygen infused to keep the water environment hostile to the pathogens that may otherwise move in. Aquariums use air bubblers to replace the oxygen that the fish use and you can do the same with a pool if it is rarely being used. Normally, kids splashing about, rain impacting the water surface or the running of Jacuzzi jets is sufficient. You don't need a lot of infused oxygen but you need some, or just enough. If the water is not being splashed about for days in a row, grab a $40 pool fountain from Amazon, connect it to one of the return water jets in your pool and the fountain will make it rain when the pump is running and that will be more than sufficient.
Cost:
Now we can talk about costs. By now you should have figured out how much water is in your pool. Look at the rating plate on your pool pump. This plate will tell you the flow rate at which it moves water through the system. Calculate how long it would take to exchange the complete volume of your pool once then add 10%. Once + 10% is the bare minimum daily requirement for filtering your pool, provided it is not being used. If being used for an hour or two a day, then two complete filtering cycles are needed. If you have a pool party and there are 20+ people in the pool, your oxygen levels will be great but your filter will need to run much longer than usual. How long your filter pump runs each day is directly proportional to how much water it needs to cycle and how dirty the water is. Monthly electricity costs fluctuate based on how often and for how long your pump operates. The same rating plate that indicated the flow rate will also detail how much power the pump uses and with that info you can figure out the hourly electricity cost, approximately. I have a large pump that eats up electricity but exchanges the pool water pretty quickly. I run my filter for about 1.5 hours a day, turn the filter on whenever anyone is in the pool, and allow it to run for about 30 minutes after the last person gets out. This works for me, but your timings will be different. You will know too much or too little by the quality of your water because you are looking at it everyday.
If your water environment gets out of control with algae of various types, not only are different chemicals needed to get things back to normal, it will also be necessary to run your pool filter for long periods of time in some cases continuously for a couple of days, maybe longer depending on how bad the situation is.
The long and short of all this is, a pool is a lot of work and just like a car, costs you money even when not being used. A little bit everyday, or a lot more once or twice a week. I would never recommend a pool be allowed to sit in a climate such as we have here in the DR for longer than week without someone being available to vacuum up all the crap that collects on the bottom, brush off the algae that will inevitably collect on the bottom and sides of the pool itself and adjust the water chemistry.
If all of this sounds daunting, then maybe a pool is not for you at this point in time. Pools are visually appealing only so long as the water is sparkling blue. The damage caused by infrequent or inadequate maintenance will result in a dull blue/green colour all the time and the only fix for this is to repaint the pool or replace the liner. You can tell who really looks after their pool and who doesn't spend quite so much time on it just by the colour of the water which is a reflection of the condition and colour of the pool walls (assuming the water is clear). You can even see the differences in pool colour on google maps.
Chemical costs depend on how much water is being treated. I have bout 5 chlorine tablets in my system at any given time. I buy in bulk at about $RD 35 each. On occasion I need to add some granular chlorine to the skimmer when the tablets are not dissolving fast enough to keep up with the chlorine depletion by the sun and/or contaminants. About half a gallon of Muratic acid a week $RD 55, algacide - 2 - 3 cups a week (a gallon cost a little less than $RD 300) and then there is my time - priceless.
Above I have detailed the basic considerations. There is more, but that's enough for now. From this you should be able to determine for yourself or have a discussion with your significant other and determine if a pool is worth the investment in time, effort and money for you. A pool is the focal point of your yard even if you wish it weren't. A dirty pool is gross, a health hazard, a breeding ground of mosquitoes and other bugs and if allowed to be come one, an ever present eyesore. A dog or two are definitely easier to maintain.