I generally agree with the 5 to 7 year service timeline. However, I would like to make some points about the Buren cal 11 through 15 movements and the cost of service. First of all, there are a number of non juby jewelled bearings (including all of them in the autowind gear train) that are prone to more wear than standard ruby jewels. In addition, the micro rotor bearing is non roller or juby jewelled and a really POOR design that needs to be oiled on a 5 year time line at the least if the watch is worn often. This part has become very hard to find and is selling up to $200 now.
Assuming that all the gears, pivots and bearings are OK, the movement still needs additional testing after service to make sure the auto wind mechanism is working properly. An 8 hour (approximately) "wear" should be done to determine how long it will run overnight. I have seen a variation of 8 to 18 hours on this test (3.2 full turns on the crown after full wind down to start the movement and second hand not engaged) after the watch is taken off. Of course this variation has a lot to do with how much wrist movement but it is a good indication that the autowinder is working. If it does not pass this test, it needs to be taken apart again to determine the problem. I have serviced at least 70 of these now and I have seen a lot of problems that you just don't find in other movements. This makes it more time consuming than any other movement that I work on. So my point is, plan to spend more on taking care of any chrono with any of these movements! I doubt that the original designers gave much thought about how they would be running after 40 years!

: 5-7 years is a good rule of thumb, 3 years is overly pessimistic.