I have had fuses replaced with Circuit Breakers. The circuit breakers keep tripping. Why?

Overloaded circuit - fuses blow on account of the wire inside the fuse blowing as there may be too much load for the fuse.

DO NOT upgrade the fuse wire to a higher density wire as this will result in burnt-out cables in ceilings and walls.
Circuit breakers trip before the cables get a chance to become overloaded
To solve this problem, either unplug some of the appliances on the circuit that keep tripping and plug them in to a point that is not tripping or get an electrician to replace the fuses to circuit breakers (if not already done)
If the fuses have already been replaced with circuit breakers and the breakers keep tripping; you will need to schedule an electrician to install more circuit breakers to even out the load