My dad has a Baja spa that is about 8 years old. It is a small 4 person spa. Has had very few problems. But the spa has about had it. It needs the following:
New Cover (8 years might be good for a cover)
The exterior skirt needs to be replaced
The inside of the spa has quite a few cracks.
Another thing to be aware of. It costs him about $50 - $60 dollars a month to run in the winter. We live in Tucson, AZ so it is not very cold.