You should always at least try to charge it before replacing it or take it out and take it to one of the auto parts stores and they will test it and charge it and retest it for you.
If you do need one though I wouldn't buy one from there because you can usually get them cheaper at Walmart or other farm style stores.
You really don't need to charge it before you store it for the winter and you really don't need to disconnect it either because it doesn't make that much of a difference but if anything it would be a smart idea too at least put it on a charger for overnight or a couple of days before you're going to try to start it at the beginning of the season.
Some people leave them on a battery tender all winter long but I don't really think that's necessary either
If you do need one though I wouldn't buy one from there because you can usually get them cheaper at Walmart or other farm style stores.
You really don't need to charge it before you store it for the winter and you really don't need to disconnect it either because it doesn't make that much of a difference but if anything it would be a smart idea too at least put it on a charger for overnight or a couple of days before you're going to try to start it at the beginning of the season.
Some people leave them on a battery tender all winter long but I don't really think that's necessary either