Hotpoint Aquaria WF740 - new bearings?

Hi. My 3.5 year old machine is starting to make a grinding mechanical noise when it spins. It's not hugely loud but definitely something is going wrong and want to find out if I can fix it. Have read some stuff about bearings. Could this be it and if so, how tricky are they to replace and is it worth it?? Thanks loads in advance for any help.