Rolex for investment, any advice?

[tomc8219]

Sorry for jumping in un-announced (just joined today) I've been collecting watches for the past few years and am ashamed to say that i've only just started with Rolex. My current collection as it currently stands holds a franck muller casablanca, a jacob & co and a breitling navitimer.

I've always bought watches with the view that one day i'll part with them hopefully for a modest profit. That day hasn't come yet (touch wood) but now I am looking for afew Rolex.

I am considering a SS 18kt datejust and also a president. Can anyone offer me any tips regarding models that hold value over time. Sorry if i'm sounding a little vauge, still building up my knowlage on the Rollies