Look at time factors for good value : if they don’t have one that suites now then you could wait as he keeps bringing in new designs whilst the old ones sell out.
http://www.timefactors.com/
Also consider servicing costs when choosing a watch, and the servicing fees will be higher the more complicated the movement, such as for a chronograph.
Watches like a Rolex might well go up, but if you get it serviced every 5 years as you should (otherwise it might not go for a premium price 2nd hand anyway) then they don’t go up that much once you remove the servicing fees.
For example my Omega Speedmaster Moonphase was something like 2.2k when I bought it new and they are maybe 4.5k now, but a recent Omega service was £440 (although it looks like new now) and a new strap is something like £250.
So to get full investment value you would buy the watch and then never wear it, so it wouldn’t need servicing or replacement straps.