NiMH Refresh

It would appear that my ~six month old Powergenix NiZn cells have taken a dump. They get unbelievably hot during charging and take almost four hours to fully charge. Instead of being left in the dark, I picked up a LaCrosse BC500 and an eight pack of Eneloops.

But, I am more of a lithium person. I love that I can charge them whenever and never worry about "memory" effect. However, I know I can't do this with NiMHs because they will get a memory. The charger does have a refresh function but the manual doesn't say how often this should be used.

My question is, how often should I refresh my batteries?

Also, when should I charge them? I really don't like to have batteries around that are partially used.

I have the same charger. I do a refresh cycle when i get the feeling the batteries lost some capacity or to revive friends ni-mh batteries that they tought were to throw away.