I've done some research in this area.. I run a hydro garden off solar (not that it makes me an expert) but I've experimented with it.
1. Solar output is rarely 100%. On a good sunny day it's probably 90%, but on a cloudy rainy day it can be 20%. Also most panels are built in a grid of smaller cells. If a piece of cloud say blocks a single cell (but the rest aren't), it can kill off that whole row and reduce your output.
2. Battery capacity and cycle recharge varies. AGM cells can go down to about 40% of rated capacity, recharge cycle of 500. Lithium ion cells can go down to about 20% capacity, have a recharge cycle of about 3,000. The more you keep the cell charged (IE don't run it down), the more cycles you will get out of them.
3. If someone offers you free solar installation, know that they are probably fronting the cost, reclaiming money for when you exceed your load (selling power back), and that typically you will simply be paying them (say half). The other 50% is helping pay for the equipment, and typically they will keep you in a contract for 20 years.
4. If you decide to go the DIY route, know that solar panels are super cheap (less than a dollar per watt), it's the storage that's expensive. I have a friend in northern california that has a 30 solar panel array, a very small battery bank, an inverter. What he does is runs off pure solar (with the battery buffering the power) during the day, and then when the sun goes down (and the batteries drain in about an hour), there's an auto switch that says "Hey, I'm out of juice" and it kicks his whole house system back over to the grid (this happens in about 10ms so computers won't reset). Obviously even being on the grid at night is cheaper because the demand is lower. Even if you wanted to go "off grid", most areas won't allow you to. They require at a minimum for you to be hooked up and pay the $20 hookup fee.
If you have the land, mount solar on the ground on a stand. You can troubleshoot easier, clean (or buff) the panels so it maximizes light capture. This is obviously much more difficult to do on a roof. Also if you have a leak (or need the roof replaced), uninstalling panels can be a big pain (both the mounting and the wiring).