5A fuses are used in older equipment, most manufacturers have now standardised plus and fuse ratings to be either 3A or 13A.
Fuses are safety devices designed to protect the electrical cable of the appliance rather than the appliance itself. Fuses are deliberately the weak link in a circuit and will blow' if an appliance or cable draws too much power, to prevent a fire occurring.
You should also only replace a 5A fuse with another 5A fuse. If the fuse continues to blow do not put a higher amperage fuse in, check and correct the reason for the fuse blowing in the first place.