One way to tell if a watch is going to appreciate in value is by looking at the manufacturer’s history. If they have a good track record and continue to produce quality watches, then you can expect the watch's value to increase over time.
The quality of the watch itself and its condition (if you’re getting it secondhand) are also crucial factors that affect whether the watch will appreciate in value. Also, the rarer the watch is, the higher it may be in value, so that is also worth noting. That’s why many expensive watches increase in value over time.