There are two basic problems with the fuses MBs use; they can lose conductivity with the fuse panel contacts, and they can fail without causing a visible gap in the contact material. I believe the advise is to replace all fuses periodically (every 5 years?). You probably spent more scratching your head on this problem than you'll spend replacing all the fuses.

I don't know that there are better or worse fuses of the type MBs use. I got a pack of spare fuses from an auto parts store. The one fuse I replaced has lasted about a year so far.

I'd like to know about fuses that are of better design/quality/longevity than the original fuses.

Sixto
91 300SE