On my 2-strokers I'll get them started and let them idle. When I can't hold a hand over the air exhaust or muffler more than 5 seconds, she's got enough warmup to go.
On the 4-cycle OPE, especially the Deere tractor; after a cold start I'll let them idle up with the hydro clutch engaged but neutral until I hear the idle rise. That warms up the sump and hydrostatic drive and she's ready for battle.
On the Impala? Start. Adjust mirrors. Adjust seat. Adjust stereo. Adjust climate controls. Light a cigar and smile. Roll down window and engage transmission and drive moderately until full hot on cluster.
On Silverado SS, same as above but wait for cold fast idle to drop under 900rpm. The gear clash is otherwise really harsh and she'll drop a transmission clean out in grenade fragments if you do it *just that one time* more.
Yeah. I'm a fan of warmup.
To my contractor and professional brothers? If you've used OPE of any kind within 3 hours since last shutdown, it's a warm start. You don't have to warmup any of it for more than it to have a stable idle. Send it!