I started noticing a problem with my electronics not working consistently about year ago.
I bought a smart charger and discovered many of my 7 day shop batteries were dead and not accepting a charge any longer.
Moved to eneloops since and no problems.
To be fair - eneloops have been going for a year and are a smaller sampling size of 8 vs approx 30 7-day shop regular and long lasting charge batteries from 2-4 years old.
Smart chargers showing you if any battery is dying are a good investment to days lost from not being able to shoot because your flash, trigger, receivers, etc aren't working.
I bought a smart charger and discovered many of my 7 day shop batteries were dead and not accepting a charge any longer.
Moved to eneloops since and no problems.
To be fair - eneloops have been going for a year and are a smaller sampling size of 8 vs approx 30 7-day shop regular and long lasting charge batteries from 2-4 years old.
Smart chargers showing you if any battery is dying are a good investment to days lost from not being able to shoot because your flash, trigger, receivers, etc aren't working.