at the end of service, whenleaving home,etc.
You should clean it everyday that you use it.
You should use it once a week.
You should use your treadmill on a regular basis. You should use it every day if possible. You should use the treadmill for twenty to thirty minutes.
as often as you (and your partner) want...as long as you use protection of course.
never
everyday
Every 2 years
Depending on how often you use your computer. Average users should do so once every two weeks
everyday
before use
There is no set guidelines for how often you should use spellcheck. Generally you could consider using spellcheck at the end of every paragraph. But really, it's entirely up to you.
The material should change color if it has absorbed waste gases. The frequency of use dictates how often you should change it, but even with very minimal use the granules should be changed at least once monthly.