Have switched to "eneloop" for quite some time all your battery powered devices. Absolutely unbeatable, that after charging these batteries can store so long (without self-discharging). I now had however again reorder, I had all installed. Even thought the sphygmomanometer my wife the "eneloop batteries" AAA, 3 months (at daily 6 - 8 measurements). This is an absolute record, other batteries made limp after at least 3 weeks.