I recently saw an article in The Wall Street Journal titled "A Cheat Sheet for Novice Watch Buyers", so of course I had to add my two cents. Paraphrasing the article, the question which originally prompted the article was from a buyer who wanted to look like he knew what he was talking about when he went to buy a watch. The writer offered five "tips", some of which I agree with and others I disagree with. Without going into the longer descriptions associated with each answer, I'll list the answers from the WSJ below and add my own opinions in response to each answer.
(1) Is this hand-wound or automatic?
First off, I would like to address this question. While many watches do not feature exhibition case backs, there are also many that do. Many companies include them, simply because they allow for an additional selling point and showcase the movement. If the watch has an exhibition case back and the buyer asks this question, the sales associate (although they most likely wouldn't say anything) would clearly realize you didn't know what you were talking about. This is mainly due to the fact that hand-wound watches will not have a rotor. In the photo below, the gold part (I picked a photo where the two parts could be easily distinguished) will rotate. He also adds that a hand-wound watch needs to be wound daily. While daily winding can't hurt, it is definitely not necessary for many watches that are available today. Released last year, the Oris 110 Limited Edition has a 10-day power reserve and was available for just $6,300 in steel ("just" is of course, a relative term). That means that one could technically go 10 days between winding.
(2) Are there other models of this watch?
I really don't have much to say regarding this question because I don't see a problem with it. However, there are other phrasings that may sound better, such as "Do you currently have any other models in stock?" Nearly every watch store has a book of models from any particular brand, so bringing in a model (or ref.) number with you (these can be easily pulled from any manufacturer's website) won't hurt.
(3) What's the ATM number on this watch?
This question is probably my biggest complaint. Not only do most watches have water resistance listed on the dial, but I have not once heard a person use the term "ATM number". There may very well be areas of the world that use this terminology, but even after a quick search of the web the only thing that came up was identity protection. Rather than asking the ATM number, say something along the lines of "What is the water resistance?" Asking about the ATM number will most likely result in puzzling looks.
(4) How do I use this or that complication?
Not to sound supercilious, but in my opinion if a person does not know how to use a complication such as an annual calendar or other relatively difficult-to-use complications, it probably isn't worth the extra money. In addition, the extra money probably isn't worth the 10 minutes a year you might save because you don't have to set the date at the end of every month. If you think, however, that a complication might be worth the extra money, say a GMT function if you travel quite a bit, then I am all for asking a sales associate how to use a complication. As the author stated, many salespeople are as eager to make a sale as to help you and share their passion. They aren't going to frown upon you for asking how to use a part of the watch.
(5) What is the full cost of ownership?
Once again, it's not a bad question, but the phrasing might be different. If you are at a boutique, you could ask about the cost of servicing. A worker at a store that sells multiple brands might not know the number off the top of their head for a specific watch (chronographs or watches with one or multiple complications cost more for servicing, for example and watch brands do not have uniform pricing).