There are not many fused panels or K&T wiring here (which dont necessarily go hand in hand). Replacing the panel is usually not going to solve a fuse panel problem as the branch circuits are often overloaded. Lights and receptacles not working is a troubleshooting issue and having experience and using a systematic approach based on that experience is imho the best and fastest way to solve those issues. You'll probably lose your ass on a few of those kinds of calls, however it is quite satisfying to me to figure out solutions to those problems.
Electricians do it until it Hertz!
The problem with old fuse panels tends to be they just don't have the capacity for what's needed.
As far as panel amperage, conductor space, 120v circuits, and 2 or 3 pole circuits.
So what most likely started as a clean code complaint install may have been turned in to a violation pic of the month by people in the past adding more circuits.
The S-fuses required 11/1941 were called "tamper resistant" in that only a fuse of that amperage would fit (up to 15a, 16-20a, 21-30a).
Replacing the Edison based fuse 1 size fits all (15a, 20a, 25a, 30a, & light bulb).
Also by design a penny behind the fuse trick does not work. Because the load side of the fuse was no longer the threads, it was the underside front lip / shoulder.
Fuse panels have no means of GFCI or ark fault protection. So sometimes you see upgrades that should have been protected with GFI or AF but were not. Just seen on fuse panel the other week. Had air conditioning, in-ground pool equipment, pool light, outside receptacles, and maybe something else added. Nothing was GFI protected. Lots of double tapes and the A/C run off line side feed through lugs. So if you pulled the main, the A/C fused disco would still be powered. Not to mention all the 2 wire NM wire feeding the branch circuits.
Plus the fuse panel locations may no longer be acceptable.
Knop-and-tube was a wiring method developed because the original wire insulation was not very good. The conductors had to keep a minimum of 2.5" apart and be insulated where passing thru wood to prevent leakage. But Knob-and tube was on it's way out in the 1930's in favor of easier Romex and BX. No longer permitted for new installs by the mid 1970's.
I can't tell you when the last distribution fuse panels were installed. Defiantly still done in the 1970's. Chicago used to require S-type panel boards for emergency circuits. It's still an option. I remember seeing probably 42 circuit fuse panels on what looked like a new install in the downtown. Was told the idea was for emergency circuits they could limit anyone from turning it back on by using fuses. Can't think of anywhere it's prohibited in the NEC except you would need to AF & GFI protect another way. Don't know if you can still buy a new fuse panel board. Except there are new old stock ones on Ebay. Imagine if you put 200 amp fuse panel on you bid. Buy a new one on Ebay and mount it. Tell them a circuit breaker panel is an extra.
They really just got a bad rep with insurance companies and home inspectors.