Hi RonaldD: here's Eric Clapton's "Blackie" - or is it the replica?
Eric wore through the fingerboard lacquer, had it resprayed over the dirty marks produced, then wore through it again. I think
it was then resprayed a second time, along with its second refret. All of that took him 17 years (if memory serves) before he retired the guitar.
However, that neck was finished with relatively soft nitrocellulose. These days all Fender necks across the catalog are finished in polyurethane (not to be confused with polyester used on MIM bodies), with the exception of a few Reissue type models which still use period correct nitro.
Urethane is very hard wearing, so it'll last you a good long time - which is why they use it on necks. And if yours does ever show signs of wearing through you can always have a couple more coats sprayed on top for years more wear.
In fact, your frets will wear out faster than the urethane lacquer. And with maple fingerboards a respray is often part of the refretting process, so in practice you are unlikely ever to reach wood through that finish.
Play your Strat with confidence!
Cheers - C
PS: OK yes, the picture indeed shows Fender's replica Blackie, not the original. Could you tell...?