Alright thanks! So, ff the problem is one batterie that is a bit weaker its normal to drop from 100% to 0% in 2-3 hours?

I bought an "Encore" model, kind of refurbished. Battery was supposed to be replace by all new. We bought the wave in May 2023 and since then it is used everyday. Many hours a day. Should I just replace the weaker battery or put all 4 new? Find it suck to buy 4 battery when only 1 is weaker....