It's nice to baby an engine as some do in their car in the belief that it will lengthen the time between overhauls.
+1
I remember at one base there were some days/nights when I arrived back at the carpark from flights at the same time as a shift of airport workers. These guys were obviously racing each other or under the impression that they were saving money becuse as soon as their engines fired, they set off down the road, accelerating madly. Made me wince every time, and all their engines sounded like buckets of nails....
Years ago I rebuilt a Rover V8 engine - rebore, new crank, pistons, new camshaft etc, etc, and before I fired it up for the first time after the rebuild, I made a tool to prime the oil pump with my electric drill via the distributor drive to pump oil through the engine before starting it. I would say it took about 20 seconds of pumping for the oil to reach the top of the engine (I had the rocker covers off so I could see how the oil was progressing). Since then, I try to let any car engine idle for at least that sort of time before putting any load on it, and even then use it as gently as possible until it is fully warm. So far, my car's engines have sounded smooth like sewing machines even after 10000s of miles.
I also wince when I see people banging on electrics, air and both packs, the very second the APU says 'available'. I try to make subsequent selections no quicker than once every 30 seconds or so.
Our CFMs need 3 mins to warm up, our IAEs need 3 mins if warm, 5 mins from cold, and both types need 3 mins at idle to stabilise before shutting down.