Both of you are posting with the intention of helping--and that's never a bad thing, IMHO.
If the cleaning/oiling history of the watch is not definitively known, then I think Don's analogy was "right on the money".
While a proper cleaning is a process that somewhat resembles an engine rebuild, a more realistic comparison would be to a tune-up--which, like watch cleaning, falls into the necessary maintainance category.
In the case of a watch, failing to do a timely cleaning can result in wearing-away of metal, shortening the life of the watch or leading to the need for more expensive repairs.
By the same token, had a cleaning been performed fairly recently, then it would be wasting the customer's money to suggest a cleaning, rather than simply focusing on diagnosis.
Popeye, if you want to do a little diagnosis for yourself, I believe that, if the problem lies with the click, clickspring, ratchet wheel or crown wheel, one wouldn't even need to pop-open the watch case in order to figure this out--at least in this case.
Since it's stopping within about 1/2 hour after a full wind----once the watch stopped, see if it requires many turns of the crown to fully wind it up or if the crown can only be turned a small amount. If you could fully wind it at this point, it would be apparent that the mainspring was unwinding prematurely.
A problem with the integrity of or positioning of the mainspring or barrel parts would show as a watch that could not be fully wound in the first place.
A relatively simple problem is that one of the hands could rubbing on the dial, crystal or another hand.
Beyond this, there are many internal causes for the same symptom, as both Don and Steve have said.
If I'm wrong, I'll gladly defer to those with watch repair expertise and trust that they will correct me.
What I need to learn to become an expert, far exceeds the amount of knowledge that I currently possess.
Hope this helps.