Dehumidifier leaking onto floor.
You should clean off the condensor coils with a vaccum and soft brush. Also, check up inside the area where the condensate drips into the collection reservoir (or goes directly into a hose attachment discharge) to see if something is partially obstructing the water flow and is dripping onto the floor, etc.
You might find that you've got some buildup of dust, dirt, and some other gunk that is mis-directing the water (condesate) that the dehumidifier is drawing out of the air.
Lastly, check the unit to see if it's level, but frankly, I highly doubt that's the issue, based on the 5+ years of good working service for you.
So long as the unit is still running and keeping the humidity in check, (if the above steps don't resolve the issue), I'd continue using it until it finally quits running, but I'd put a plastic boot/shoe mat under it to catch the small puddles of water.
The dehumidifier should draw the small puddles, so it'd be less expensive to get a $4 boot mat than dropping another $240+ for a new unit, as your's seems to be working fine, aside from the occaissional puddle issue.
Hope you find this Very Helpful and best regards!