#1 You have a serious medical condition. When your doctor has told you not to do any vigorous exercise, you don’t need a treadmill. However, doctors are prescribing exercise for a surprisingly wide variety of conditions these days. Very heavy people, and those recovering from surgery are often advised to simply walk. Treadmills can make that more convenient, but you don’t really need one.
#2 You don’t have room.
If you simply don’t have room for your own equipment, you should join a gym and use the treadmills there. However, almost all home treadmills now foldup and can be rolled away. There is even a model that folds down so you can slide it under your bed.
#3 You can’t afford it.
A good home treadmill costs hundreds of dollars, sometimes thousands. Gym memberships typically cost more than a home treadmill over time, but you can probably start with monthly fees that fit your budget. Treadmills for very heavy people are far stronger than most treadmills, so they cost a lot more. If you are very heavy and have limited resources, you may want to use the big treadmills at the gym instead. Maybe you can just walk outside.
#4 You are a very serious runner.
Very serious runners tend to prefer running outside or on a track. Though treadmills produce an experience very similar to running on a track, it is not exactly the same. Treadmills do cushion the impact and are easier on the joints than running on a hard surface, but some runners prefer the track anyway.
#5 You’re not committed to an exercise routine. The #1 reason people regret buying a treadmill is that they just stopped using it. If you lack motivation and discipline, you won’t exercise and your money will be wasted. Wait until you want it more.
You can come up with many more reasons not to buy a treadmill. In fact, you could think of so many good ones that you would perfectly justified in not exercising at all. But maybe you should concentrate on the reasons you SHOULD buy one, eh?