I've lately noticed a change when the starter is turning the engine.
Until lately the engine always started very quickly after engaging the
starter <1 second.
Most of the time when cold, and maybe a third of the time when warm, the
starter cranks longer than usual.
This morning it cranked for several seconds without starting.  Shut off and
tried again, it started quickly.
Nothing unusual on the timing of the wait light or the sound of the lift
pump.
The 2001 truck has 170k miles, and the starter is aftermarket, about a year
old.

Anything to test, etc to explain longer crank times?

Thanks,
Bill