Geez, twice a month? I let them sit 5 years and there is no
problem, except a slightly longer initial charge time.

The electrolytics in electronic flashes do seem to take rather a long time
to recharge the first time they're used after sitting for a while. Whether
this is due to deforming, or completely discharging, I don't know.

My experience in restoring the Polaroid #355 flash is that the electrolytic
caps, though almost 40 years old, are rarely bad.