I have done some research on this subject and have talked to several World Class Techs and Corvette suppliers who seem to know about this issue. First, the battery is activated when it is manufactured just as all batteries are, there is no "sleep mode". The discharge rate with no load is miniscule. Second, when installed in the wheel and placed on the corvette, and the TPS system activated, it sends a signal to the computer, again miniscule when the corvette is at rest. The drain on the battery is when the corvette is in motion when the signal is transmitted to the DIC. GM and after market suppliers rate the battery life to a minimum of 5 years and up to 10 years if lucky. This is based on the driving life. GM figures that 12K to 15K is the average mileage driven per year. So if your sensor has 60 to 75K miles on it, that equates to 5 years. The less the mileage, the less the years. My 02 coupe is still going strong and it is in it's 9th year, but only has 29K on it, or two + years. Just put new Michelin A/S run flats on it and did not change the sensors as they checked out okay before and after the install. Of course, battery life is an average, so 5 years may be the max. Based on this, I would expect your sensor to function for many years, dependng on the miles driven. I hope this helps and if anyone has more infor, please add to the post.
Barrett