My flash unit has been accumulating small burn marks on its window. Is this normal wear and tear or equipment damage?
Meltdown of flash front lens will happen when too much heat has accumulated. The temperature of flash will rise with
The more those conditions are true, the more likely will you burn the front lens. Some flashes have temperature control circuits to keep you from using the flash when it's too hot already. However, sometimes running a hot flash cannot be avoided to get the photos you want; so yes, I'd consider it normal wear and tear.