Beside the use of CO2 (described here) or contamination/mixing of your sealant with other products (described here), the “hair dryer” effect is a common but seldom recognized reason of sealant reduced life span.
When it happens:
trying to inflate with an air compressor a “difficult” tubeless tyre, it’s easy to insist, blowing air (and here the analogy with an hair dryer) for a long time before the tyre actually starts to inflate.
What is this “hair dryer” effect about:
the sealant, being exposed to a forced surface evaporation due to the fast air-flow (if the valve is down, the sealant takes the air blow in full force,) starts polymerizing. Looking at it, it reminds of milk gone bad and semi-solidified.
if there’s plenty of sealant inside the tyre, the low quantity that turns solid won’t have a major influence on the sealant life-span. On the other hand, if there’s just the bare minimum, it’s possible the tyre finally inflates and holds air, but there’s hardly any liquid sealant left inside for puncture prevention.
How to avoid it:
if, after ten seconds of blowing air, the tyre doesn’t seem to start inflating, it’s better to stop and try one of the several ‘tubeless aficionado’ tricks (wetting the tyre beads with soapy water, removing the valve-core and blowing air directly through the valve stem to maximize air flow…).
It’s also good practice performing an inflation test before adding sealant into the tyre, to locate major air-leaks or inflation issues, saving the sealant for later.