Quite a few have mentioned cleaning the fuse holder contacts. It is a scientific fact that contacts have resistance, but in practice the contact resistance of the fuse/holder is probably less than the fuse itself, and unlikely to change by removal/reinstalation of the fuse. IMHO, if the fuse holder is bad enough to make a difference you may have serious corrosion problems elsewhere in your gear.
Lets not get hung up on fuses. How about other tweeks?
Lets not get hung up on fuses. How about other tweeks?