Fluctuating fridge temp

[AnsweringTheTelephone]

I've recently bought a fridge thermometer for the very old built in fridge that came with our house when we bought it, and during a 24 hour period the temperature fluctuates between 1 degree and 10 degrees - that's not right or good is it?

Follow on question - how easy is it to change a built in fridge freezer?!?!

I think domestic fridges do go through a heat and cool cycle every day (to get over frosting issues) but I'm not sure what temp range you would expect. My new fridge is 7C at the top but significantly cooler at the bottom (as you'd expect - hence raw things are on the bottom shelves).