I just bought my first Mikrotik router (a RB1100AHx2), to use as a router on my work. We have a policy of planned substitution of hardware, in order to avoid problems.
But I have no experience with routerboard. What kind of useful service life should I expect from this hardware? 3 years? 5 years? I don’t want to change the hardware after it fails: I want to change it before. 
Consider 2+ years easily.
For CCR, 3-4 years+
Can’t say I’ve ever replaced a dead 1100AHx2 . Had a couple that came with bad memory from the factory
I have 2 now touching 4 years (received in March 2012) that I will be decommissioning in September.
On the safe side I would stick to 3-4 year replacement intervals for Mtk gear.
Great devices.Mikrotik really knocked it out of the park with this one.
I suggest you probably buy a spare one soon as I’m sure it will be EOL’d one of these days (Was announced Sep 2011).
I have had 5 running for 3 years without issue. still peforming well.
Ah, that helps a lot! Thanks for the info.
Guess I will stick with 4 years of life, then.