I have never own a Regent but I would put together a list like this to check any tractor i was thinking about buying:
1. How many hours on the machine (divide the hours and years to determine how many hours a year were put on the tractor)
2. Maintenance records on when oil was changed any major problems?
3. Looks, does it look good or does it look like it was rode hard and put away wet. Is there lot of paint scape/dents, broken/welded items.
4. Does everything work as it should, lights, starter, deck engagement etc.
5.What is the cost for a new machine like this?
6. Was it used at a residential property or was it used for commercial use.
7. How much land did the owner mow, was the land flat or is it all hills.
I would also look for answers from the knowledgeable people on this form to tell you if there were or if they have had any problems with this year and type tractor.
If you can answer the questions above and like what you have found out , go with gut feelings.
I'm new to this form and I find there is a great amount of knowledge to be learned here. Hope this helps