Is it worth it? Money wise that is. I am imagining that you use the inverter and batteries most of the time and have a generator when ever the batteries lose charge. How much is your operating costs on a monthly basis? Are you able to run AC units, fridges, TVs or do you have a Wattage limitation?
My monthly costs are negligible.... the sun charges the batteries, the batteries feed the house.
The generator is used if the sun is weak/poor for a couple of days or in the shorter days of the year if we have used a lot of power.
More solar panels woul reduce generator time.
We live normally, no A/C but a double door fridge, internet, TV lights, music all day.
As others have said, LED lights where possible, 5W squigglies otherwise (5W delivers 40W of light or so)
The pool light went from 200W to 12W by going LED.
Having no power outages or surges is a luxury hard to quantify. Peace of mind in our 6 month absence that things are operaing well.
We check the battery charge regularly to protect the integrity of the batteries and extend their lives.
Truly, the monthly cost is just the fuel if we turn on the planta - 1 or 2 hours of operation each time.
Minimal