I use the cheap $50 ones on my car and my truck and they work fine. The better ones wake up faster. The one on my car gives me readings before I get out of the driveway, the one on the truck takes a mile or so before it starts. The big problem is they dont normally have the range for a long trailer. I had a more expensive unit ($200) on my RV because I wanted to keep an eye on the inside tires in the rear and a tow dolly. That one worked very well, you did not have to move to get a reading just turn it on and in about 5 mins all tires would give current readings and updated faster if you were in motion. I get about 2 years battery life, maybe a bit more then I just replace the batteries. They all come with a tool to unscrew the cap and a couple extra O ring seals.