If the fuse has blown, then generally speaking there is a fault with the appliance which it is protecting
As someone who latter years was spent in servicing electronic equipment I would say that a lot of the time it's just that the fuse has "got aged" and blown for no apparent reason. If the fuse is rated close to the running current of the appliance then it tends to bend at power up and it also sheds a minute amount of metal, end result after awhile is it just dies. If I had that problem a lot on a piece of equipment I'd substitute a "slow blow" fuse of the same rating. (I'm not talking about plug fuses which are only,or should be, to protect the cable going to the unit.)