The same laws of physics apply to the fusable material in an inline fuse as a fusable link. If your fuse is failing from fatigue you may be using the wrong fuse.
If you replace it with a slow-blow device you have now changed the weakest part of the system to something else, perhaps the very part the fuse was intended to protect.
I've never been a fan of fusable links, but more important is to understand why you would use one versus why you would use a simple fuse or circuit breaker. I'm pretty sure the major manufacturers used fusable links because they are cheaper to make and install than big fuses. It doesn't take much of a savings to motivate Detroit to do something cheaper.
