Do not leave car running unattended, EVER! You must be there for a retest.
Stop drinking. The interlock will pick up alcohol in your system from the previous day.
Don't eat or drink (only water) 15 minutes before using device.
Avoid mouthwash, toothpaste, chewing gum and candy 15 minutes before using device.
Avoid lending your car, borrowers must be trained by you on interlock.
You must comply with any retest request, even if you are about to turn off the car.
In-car environment: Air fresheners can give you a bad sample. Remove all air fresheners!
Do not leave the handheld in the sun. Shove it under the seat or cover it.
Extra mouthpieces are available at the service center.
Weak vehicle batteries will cause you grief, you may need to replace your car battery.