RE What to do when you buy new tires.
It is normal for most reputable tire shops to replace the valves on a car when you get new tires. The valves are rubber and get old.
People forget that bolt in valves have rubber gaskets which should be replaced when you get new tires.
Valve extender hoses have rubber interiors which also get old, so these hoses should also be replaced when you get new tires.
Think about how you would feel to buy a new $300 tire but not pay $5 for a replacement valve only to have the valve fail, causing the tire to fail, resulting in $1000 body work.
New rubber parts in the valve & hose are cheep insurance.
Retired Design & Quality Tire Eng. Read my tire blog RVTireSafety.com
to learn more about RV tires, valves & wheels. Read THIS
post on why Tires Fail