Point noted, maybe watches ain't my type of side line
investments as generally will depreciate over time. Thanks
Good choice, tankee.
Still, don't throw the baby out with the bathwater. Watch
collecting can be fun, even if you're not buying a stack of
Rolexes, and anticipating how the market will appreciate is an
interesting exercise in itself.
For example, I started getting interested in Tudor chronographs,
and after doing some research over three months I saw that prices
were rising for the 791XX series, which were distinctive for their
"big block" cases. Getting ahead of the trend, I picked this
one up for A$2550:

I've just seen the same model being sold in Germany for
A$9998. I buy my watches to keep them, but it's still nice
knowing that I've almost quadrupled my money in two years doing
absolutely nothing.
Then again, the market's unpredictable. I could recommend
that you pick up an M-series Rolex 16710 with the 3186 movement -
they're an interim model and are likely to be rarer than the
older versions with the 3185, and by that measure could be the next
Rolex 168000 Sub, but who knows? Rolex might just keep making
them and flood the market, making it as much of a lemon as the
Green Sub. On the other end of the scale you have sleeper
hits like the Milgauss and the Daytona, which were not Rolex's big
sellers originally, but exploded in the collector's market years
later. Part of the fun's working out what makes specific
models valuable. For example, why would anybody pay $165,000
for this?

I'd love to say this was mine, but it belong to a fellow
collector, and he got it at a bargain. Go figure.