After 4 years of use my Tamron 150-600 VC was jumping really badly when activated. I opened a ticket on their website and sent in my lens. They fixed the VC and cleaned the inside of the lens under warranty. Turnaround time in total was about 8 days and all parts and labor were covered. Very smooth and simple transaction, so thumbs up to Tamron. I'm an old timer so it felt a little odd doing this entire transaction without ever speaking to anyone. Everything was just form based on their website.