Is there some unspoken rule to not use Esuna/Leech?

[Lemuria]

For most status effects, I'll remove them as soon as I'm able, but there are a few exceptions to this rule.

1. Poison. Some poisons are re-applied almost immediately after being removed. In such instances it's better to remove it after the fight instead of constantly spamming Esuna. These poisons tend to be low-strength so it's rarely a problem.

2. Pacify. If I'm mid-cast, then trying to Esuna Pacify is meaningless. It'll fire after the effect wears off on its own. If things are pretty slow-paced I can usually remove it very quickly since I'll see when Berserk is wearing off. Just don't rely on it.

Those are pretty much the only exceptions. Anyone not removing debuffs in any other situation is just a poor healer.

Silence is a top priority to remove, especially if it's on another healer.

The one thing i'll say here is that there are very few Silence debuffs which last long enough to Esuna. I can think of one example only, and it tends to silence EVERYONE (Wandering Palace HM) so unless the healer has Echo Drops, you're kind of screwed.

Incidentally, I've always kept a small supply of Echo drops on my healer at all times. It's a throwback from my FFXI days when you basically sucked if you didn't at least carry some with you.