I use 5A fuze at the battery and a 5A C/B for everything in the panel.
Don't ever remember blowing a fuse. I have had wires break, fuse
holders not keep good contact, plugs fail to do their thing, etc. My
latest problem was a "clunking" noise, turned out to be the plug at the
end of a 6 inch battery lead, clunking against the deck. After about 10
flights of clunking, the wire broke at the end of the solder connection
to the battery. Now have the plug epoxied to the battery. BTW, we need
2 batteries and 2 varios and 2 GPS's and 2 data loggers, etc to make
everything 100 % reliable. When my wire broke I was 40 miles from home,
switched the Borgelt B-40 to "internal" power and had a vario and audio
to get old JJ back home.