This 20 Gallon 4HP air compressor features 100% continuous duty cycle.
There is no exact marked lifespan hour on the page; the oil-free motor generally has a service life of over 1000 hours under normal use.
It can absolutely work for your plasma cutter that requires 7.5 SCFM delivered flow rate, because it provides 10.66 SCFM @ 90PSI, which is higher than your required 7.5 SCFM.
By vevor