rechargeable batteries question

im posting this in the camera section since i use these batteries with my camera. it's a Canon Powershot sx130. Has anyone had any experience with these batteries? they're the Energizer rechargeable NiMH batteries. I got these 2 years ago exactly. it came with the charger and 2 sets of batteries. at first they worked great, they lasted me for a long time in between charges. I used them for both taking pictures, and recording whole concerts from when i saw live bands. just within the last couple of months i noticed they seem to die faster. when i record concerts i have it set to record in 720p HD which i know drain the batteries faster than recording in normal 480p. it seems when there are times i just take pictures and repeatedly turn the camera on and off and zoom in and out so maybe thats why they're dying out faster? the 1st set dies out i always have a spare set to replace those. when i record concerts, before they would give me about an hour and a half of footage before signaling that they're dying. now 1 set cant make it to one whole live band which means i have to replace them with the 2nd set to continue recording. also, when i fully charge them the charger say they're fully charged yet if i dont use them for a few days or couple of weeks i recharge them just in case and the charge meter says they need about 2-4 hours to charge before they're fully charged. is it maybe since they're 2 years old that i just need to replace them with new ones?

http://img.photobucket.com/albums/v3...r/IMG_1583.jpg