If you are going to rollover there is something to be said for _less_ bits and rolling over more often. Imagine a system with 3 or 4 digit day counters that rollover. Systems with 27 years until the first rollover are more likely to end up with some broken code, perhaps written by consultants, or "temporary hacks" that need fixing before rollover. Even if they dont have bugs they have 27 years of code without testing the rollover so when it looms they will have a y2k type effort to be on the safe side.
Those with 3 year rollovers will have code tested earlier, more often: less bugs and cheaper to fix.