OK, the issue with electrics is battery life. Most simple chargers cook the batteries. It's from two sources. The inability of the charger to sense true battery condition, and the actual condition of the wiring.
So the quick way to tell if a used cart has decent batteries is to look at the sidewalls ... If they are bulged, the batteries have been cooked. Their life has been shortened by 1/2 or more. If the batteries are square and flat sided, there is a chance they will live a long time.
The best scenario is for you to replace the factory wiring in the battery group with at least #4 welding cable with crimped and soldered lugs. I like tinned lugs, but any good high quality pieces will do.
The next big issue is to keep the batteries clean and dry. The schmultz that accumulates on the top of the batteries is corrosive and is also a chemical semi-conductor. It ill eat the cart parts and it will drain the batteries, and throw off the charging cycle.
The best affordable chargers I know of are Noco Intelligent units. You can get two and three bank chargers. And you can wire in plugs/receptacles in the cart to allow charging in banks of 12v. This means that the charger never sees the sum/series wiring. If there are any faults, they are isolated to one bank. Noco's will charge, float, and condition batteries. They will not overcharge, and they will not cook batteries.
If all is good you can get 7~10 years from a set of batteries. That is a lot of quiet golf, and no dealing with ethanol and 2-stroke carburetors, or 4-stroke valve adjustments, etc.
Although I play Golf, I did not learn this from actual golf carts. I learned it from our son who is an EE and from the local Park that uses quiet golf carts and related electric utility vehicles for internal park service work. Their carts were dying and giving them fits. He went and helped them rehab/rewire the carts and mini-trucks and they were all surprised that they ran better than new. And no more issues with battery bank purchases. He laid out the whole maintenance pan with weekly wash-downs of the battery groups to keep them clean and dry (they are run 8 hours a day, every day). All the issues went away
Now they buy the good used batteries from Interstate when the local courses turn in the whole lot of their batteries every 6 months or annually. Interstate sorts out the cooked ones for recycling and sells the good used ones for $80. So getting an electric cart up and running is not that cost prohibitive