<VV>When them tire stems get rotten...

[Padgett]

>It cost me a couple of hours and $30 to have all five stems replaced
>and the tire with the nail repaired.

Yes, stems do get rotten. Problem is that to tell if they are rotten you 
have to pull hard which may make even a usable one fail. Catch 22.

If really concerned, you might consider metal valve stems such as the 
Milton 470, Rubber bits are clamped and I have never had one fail.
http://www.toolsource.com/ost/product.asp?component_id=&vehicle_id=&user_id=&IT_ID=&brand_id=,&sourceid=http%3A%2F%2Fwww%2Egoogle%2Ecom%2Fsearch%3Fsourceid%3Dnavclient%26ie%3Dutf%2D8%26rls%3Dgglg%2Cgglg%3A2006%2D11%2Cgglg%3Aen%26q%3D%22milton+industries%22+470+&dept%5Fid=500&pf%5Fid=65326&mscssid=NC9DC4ABQQMC8JKLLHJK19PGXT1AFVG7 
- or http://tinyurl.com/ejm3g )

Padgett