Years ago I inherited my grandfathers 1932 Hamilton Pocket watch. I had it serviced and recently started carrying it. It failed and I had it serviced to the tune of $130. It is railroad accurate (+4 to -4) seconds per day). One thing led to another and I purchased the most accurate pocket watch (mechanical) made-Hamilton 992B. I purchased it on ebay. It failed and I got it serviced. Meanwhile I bought another on ebay and it shortly failed.
Lesson: never buy an unserviced mechanical watch..period.
I purchased 3 additional ones (two I got really cheap (< $300)
I have purchased other cheaper pocket watches, like Westclox. Two were new in the box.
At this point it would take an amazing deal for me to buy another. Odly, I many times carry my new-in-the-box Westclox