pete h --- If it works don't fix it!
We use a 110 amp battery and use it on regular outings (we have been away in the 'van 3 months this year!). If you keep it fully charged you should be OK for a bit longer yet.
At home we have the facility of keeping it hooked into our household electrics and tend to go on electric hookups when away - this keeps it in tip top condition. We also use it in conjunction with a motor mover to negotiate a steep turning gradient when leaving/arriving home.
If you find that it begins to discharge quickly, perhaps a new one might be in order. Until then keep your money in your pocket.
Ann