WSB1275-75Ah Maintenance-Free Battery - Recommended ESP25n, WSS30Vn Basement Guardian Back-Up Sump Pump Systems

How do you tell when the battery needs replacing?

What to do with the old battery? when buying new one in store i bring old one there for recycling. but when buying from amazon?

Looks like black magic on batteries. can i successfuly use 100ah agm batt. rather than 75agm batt. on esp25? have cooked 3 esp25 and 3 wet cell batt.

My battery came without terminal bolts. I tried a couple sizes from the auto store. None fit. Any idea what size the threads are.