Nightmares in adults are often spontaneous. But they can also be caused by a variety of factors and underlying disorders. Some people have nightmares after having a late-night snack, which can increase metabolism and signal the brain to be more active. A number of medications also are known to contribute to nightmare frequency.
The original DVIR must be kept for three months from the date it was prepared. Drivers are no longer required to carry DVIRs in the vehicle. Back to Vehicle Inspections & Maintenance Main Page Shop Forms & Labels View Training Encompass Fleet Management System Order Manual
As Scott mentioned, they can last longer than 9 months but if not, you have the other retainers. In short, you have retention for a minimum of 3 years (if you don't lose them). $575 for 3 years is a very good deal for Vivera retainers. Lab fees for those are very high.