Example Lifeline Storage Voltage Slump

Seven years seems fairly good to me.

Not sure what this OP is all about, but concur that you must charge up any battery you buy new off the shelf. It will not be "full" when you get it, and might be a bit sulphated too.

Recently got new Wet 6s at a store with slow sales on 6s. So dated Feb, bought in April, it took three runs with the 1093 VECDBD set to 4 amps and with Equalize set. Ran for some hours first time, and SG was not up, second run still SG not up all the way, then third run success! SG up to a decent baseline SG around 1.290

Same with car batteries--got to charge them up on getting them home. AGMs too. I have no experience with Li batts, but I would do the same first thing I got one home to see it balancing at the top end for sure, and also to then be able to reset the AH counter to zero.

I would not get any battery home and just slap it on the solar or converter to float or whatever comes next. Might just be firming in the lower capacity from being on the shelf as your starting point instead of cleaning that up first, then going from there.