Yes, you should lubricate your treadmill. No, you shouldn’t spray it with WD-40 or something like that. Many treadmills will void the warranty if you use anything outside of the manufacturer’s approved list of lubricants. Oddly, this list only ever includes their own products.
If your treadmill came with some kind of lube, hold on to it and use that maybe once a year to keep things good under the hood. If you don’t have any treadmill lubricant, DO NOT use something like WD-40 or oil or anything like that. You can actually damage your treadbelt with these products.
My recommendation is to go to a hardware store and see if you can find some grease or the easier thing might be to check out these lubricants from Treadmill Doctor. These will not damage your treadmill and you can get a cleaning kit as well to keep your treadmill in good shape.
Unfortunately, all treadmills require maintenance. There is no way around this. If you don’t maintain your treadmill, then it will require repairs. Either way, no treadmill will last forever so if you want yours to last long, be sure to take good care of it with some lubricant and cleaning each year, maybe even twice a year. But remember, don’t just spray WD-40 on there and call it good. In fact, don’t ever spray WD-40 on there. Stick with items from the manufacturer or the products from Treadmill Doctor.