Cluster light fuse keeps blowing

Those aftermarket gauges are always suspect, check the lighting wires to them.. Also an aftermarket radio if so equipped is a likely problem source... The randomness points to a wire chaffed and grounding out.... A shorted component would likely pop the fuse every time the dash lights are lit.... When the dash lights are off the fuse isn't gonna pop, but taking fifteen minutes to pop means it's not a hard short...