BT writes:

Changing the trim setting does not change the set screws (Stop bolts) that
limit the amount of Rudder, Aileron or Elevator travel.

But it does control how far you are from each stop.

If you trim to pitch the aircraft upwards, for example, in order to
eliminate the pesky need to hold the yoke way back, you may only be a
short distance from the limit of your elevator travel. If you then
become complacent and forget how much you've trimmed, and you suddenly
need more elevator travel, you're out of luck. With a more neutral
trim, you have plenty of travel in both directions if you need it.

You can adjust your throttle so that you can remain level with zero
trim. Or you can adjust your trim so that you remain level, pitching
upwards as necessary. In the first case, you have plenty of safety
margin on both sides; in the second case, you have very little margin
to pitch up further, and if you suddenly need to climb and cannot, bad
things can happen.

This is why I prefer to stay near neutral trim. If I'm not in a rush,
for example, I'll maintain altitude by adjusting the throttle until I
can trim to zero. That way I have full elevator travel in both
directions if I need it. And since this usually results in a lower
throttle setting and slower speed as long as I'm not close to my
ceiling, I have a good margin for thrust and speed as well.

I will make an exception sometimes and trim down for high speeds,
since that isn't as risky as the inverse.

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