It's easy to lose motivation to go to your gym if you have a long commute or work multiple jobs and making a pit stop at home to grab a change of clothes takes precious time. Lifehack.org suggests keeping a gym bag in your vehicle when you leave the house so you'll have one less excuse not to exercise.
A good gym bag will include workout wear, a water bottle, a towel and perhaps a media player. As long as you have these things in your car, you're ready to work out even if your schedule shifts. Hit the link for a few more tips on how to stay fit despite a busy schedule.