I have 4 cordless phones and run them on rechargeables. Wanted to buy uncharged ones, but few and far between so paid a bit more for some '5 year guaranteed' Duracell, pre-charged. They needed charging when I got them and are no better than any other ones I've had over the years. They do hold a minimal charge for days, but I'm loth to start a conversation when they're so low and prefer to wait until they die before recharging.. My other phones often just die when someone calls or worse, when I'm getting a code call for a savings account and have to rush downstairs for another phone.
I remember Maplins' rechargeables used to be quite good. My friend recommends Panasonic, so I'll try those next time, but I've gone off Duracell, whether they be super, extra super, ultra, super ultra or whatever useless label they give them.