I have two cordless phones, and when they were new, the batteries last 3 to 4 days, then after a few months or so of usages and charging/recharging, they no longer hold charge as long, and it gets worse and worse until the charge will hold for only about 15 minutes.
I understand those batteries have memory and you have to let it die before you recharge and if you leave it on the charger too long it could also ruin it. However, I simply cannot manage to do that, I have two cordless phones and I don't want them to die in the middle of a call, so I do charge them before they run out, also I don't remove them from the charger as soon as they are done, I sometimes leave them on the charger too long.
I have purchased new replacement batteries and they work for a few months and then back to not holding charge again.
Are there cordless phones out there that will hold charges? I am ready to toss my two phones into the garbage!