How long are spark plugs lasting ?

[TurboTdr3.8]

I was wondering how long you all are getting out of a set of spark plugs , race and street , just a rough miles would be fine ?

 

[ZNix]

I just replace them every spring when I change the oil. Should last a while.

 

[bison]

I had a set last 2 years at 550-575hp. The gap was around .030 installed and about .035 when I removed them. I could have re-gapped and continued running them