Every two hours or as necessary in a restaurant setting.
every 12-18 months
weekly
According to my dealer, it should be changed at 150,000 km.
Passwords should be changed every month.
weekly
When its old
When it is dirty.
When it is dirty.
Bass strings should be changed every 3-6 months, depending on how often you play and the sound quality you desire.
The Aprilaire filter should be changed every 6 to 12 months for optimal performance.
30000 miles
If you do not drive it often, I would recommend getting it changed every 3 months. That is what many mechanics tell you to do.