And despite what the statistics would seemingly indicate, a disturbing number of inflight incidents occur after departing with a legal MEL on the related system.
I’m aware of 3 depressurisation events in my own airline following legal MEL bleed dispatches, and one famous 747 nose-gear-up landing which was dispatched with a legal hydraulic pump MEL.
Beware the MEL, because while the mathematicians say a further failure is unlikely, they don’t look at the additional load on the remaining systems.
The remaining systems will have been tested to handle the additional load during certification, but when was the last time they were stress-tested to that load prior to your impending departure?
In the case of a B737 pack, it will be running at high flow, not normal flow. When was that last stress-tested?