How often should creatures get general feats?

[Endarire]

Question
Let's assume feat power remains as-is.  How often should all creatures (that means PCs, NPCs, and "monsters") get general feats?

Sample Feat Progressions
In 3.5, cretaures get a general feat at 1HD, 3HD, and every 3HD thereafter.

In Pathfinder, cretaures get a general feat at 1HD, 3HD, and every 2HD thereafter.

In Frank & K's Tome articles, cretaures get a general feat at HDs 1 through 6 and at every 3HD thereafter.  This assumes creatures use 3.P feats, not Tome feats.

In some house rules, creatures get a feat at every HD.

[fuinjutsu]

Depends on how you want your game to run.

In the no-vancian-magic Psionics/Incarnum/ToB/Invocations/ToM games I like, feat every level is nice.  It really helps Incarnum and ToB classes shine.  Incarnum based builds are notoriously feat starved.

[McPoyo]

In the last 4 years, all but one game I've run has used an "Every Odd" progression. Never had an issue.

[awaken DM golem]

How many level 0 spells do you need, when level 4s are changing the world?
How many level 1 spells do you need, when level 5+s are changing the world?

I mean, it's nice flavor, and historical to the game ...
but a some point, feats are either almost meaningless,
or they are cheese facilitators out in la la land.

It's pretty rare for a non caster to get a feat at level 18
that's equal in power to a full caster ... unless
you take Leadership at that level, and get a full caster that way.

[Mixster]

The problem with feats is probably the huge power gap, feats simply aren't balanced against eachother, toughness for one, can give you +3 HP, while something like Power Attack or Improve Damage Reduction can be much more useful. And then there are the sick feats, like greenbound summoning, and Divine Metamagic. Who would ever take any of those stupid feats over +3 Hit points? It's just silly, it's because Toughness is broken.

If someone choose toughness at each odd level, while someone else scour the system for feats that are actually helpful, we can safely say who will end up doing most(if you are thinking the toughness guy, I have to disappoint you, Mr. Tarrasque isn't optimised that way).