Shit happens — like traveling, schedule changes, work craziness, basically just life in general — and that's going to throw off even a consistent exerciser's motivation. "It's a natural cycle: Motivation is high, then starts to decrease, then we recommit and it's high again," Sulaver says.
With that in mind, plan time off from working out as part of your exercise routine. For example, you can plan to take a full week or 10 days off every other month to rest your body and enjoy a mental vacation from the routine of working out. This will make you less likely to feel the need to bail at random times. (And by the time your exercise vacation ends, you'll probably be psyched to get back to it.)