Buyer beware.
I'll say no more.
I'd second that.
I sold some London work to guy. He had bought a round the year before sight unseen! There were streets on the list which he got after parting with his cash, that did not even exist!
I met him on the street where the worklist started, he paid the money and I took him round in my van and introduced him as a friend who would be doing the work from now on. I put a letter thru the houses that were out, I would expect no less than that.
Even on well established work some will still fall off, but if you look after it you'll keep most of a well established round.
Ask questions like, why are you selling? When was it last done? Are you regular?