A fuse that lasts 20 or more years of daily use is not significantly under-rated. The same fuse rating and type from same maker should work fine for as many years into the future.
You can actually determine how many starts a fuse will last through, if you know the start current and time duration of the start.
Every fuse has an "I^2 * T" rating (current squared x time). You may not be told that rating, though. Some manufacturers always give it, others not.
That rating is the energy it will take to blow. Depending on how close to that energy your start is, it may blow in under 10 starts, or last many hundreds of thousands of starts.
With smaller glass type fuses, you can see the fuse element "squirm" under the inrush current. The fuse can open from a melting effect, after the wire has been thinned by partial melting, Or, it may fail from a mechanical flexing due to thermal expansion. If it partly melts (extreme cases) you can sometimes see the element has "sweated out" tiny globs of material.
The bad thing is that the very same nominal rated fuse from different manufacturers may have very different values for the "energy rating". A higher current fuse may actually have an energy rating the same as a lower current fuse (or even less).
It just has to do with the material in the fuse, melting point, thermal mass, etc. Figuring that out is why the fuse companies get the big bucks (at least for the good companies, import copies are different).
If the spring loaded portion opens, that is more from the "time" part of the formula. The start was not an excessivly high current, but it lasted a long time.
If the fusible section opens, that is more from the "current squared" part, the peak current was too high during the start. That guides what is needed to keep the replacement fuse from blowing.
