I do not suggest you replace anything until you have a definite reason to think it is the problem, not just a guess. Until we know exactly what is going on (eg. fans running, compressor running, frost pattern on the evaporator, etc.) *at the time of failure* it would be premature for us to suggest what the possible cause is, let alone one of the most expensive parts of the appliance.
If you want to take the chance, that will be up to you to decide. Sorry.