That sounds like a good rule to have.
I don't really have any hard, clearly-defined boundaries myself, but recently I've learned to prioritise my internal decision-making process when I'm under external pressures.
I used to go along with what everyone else suggested, because I didn't want the stress of having to argue or fight back against an idea I didn't agree with. I had been conditioned to avoid conflict because it was usually too much of a hassle to resolve when it could've easily been a calm, balanced conversation instead. So I'd just throw my hands up and say "Ah, whatever you think is best." And then be surprised or resentful when the ugly results inevitably showed themselves.
Now, I try to cross-check what someone else says is a good idea against my own judgements, rather than skipping that step entirely. It's like keeping a background application from crashing by giving it a higher priority over resource use so it won't get crushed by everything else.
This all sounds very vague, and that's because it is, but it's just the attitude I've been trying to maintain so that my inner voice doesn't get drowned out for being too quiet.