I have Pre set on our fire dispatch channel, since our guys dont understand the concept of keying up and waiting for the crappy repeaters to open up so everyone can hear us.
I have Pre ID set on the dispatch repeater, that way, my guys have to wait for the beep, then they can talk, and the squelch on the county repeater is so slow, the swawk doesnt make it through the audio.
Now, on our fireground channel, the PTT ID is set for post, that way an important message can go quicker, and no one has to wait for the beep.
Now, I'm just waiting until the 800 system takes off, and then have to re-train my guys to wait for the beeps.
On my company channel at the shop, I used ot have pre & post turned on just to aggravate the other techs.....