I used to have to turn the dial on thermostat for my electric baseboard to a 15 in my room, then I'll hear a click and the baseboard starts warming up. Now, 4 years later, I have to turn the dial a little pass 20 for it to click. Anything thing lower would start the heat. Why is that? It's only the master bedroom that I turn on the elec heat.

The temp sensor may be bad or the bimetallic element in the thermostat could be fatigued. Does it heat properly and switch off at desired temp?