When is it the best time to mutate hatchery into lair?

I wonder

 

When you finish harvesting your second batch of 100 gas. (First 100 gas went to zergling speed)

 

Yeah pretty early, its not very expensive so when u get the gas to do it ... do it as soon as possible.

 

well, imho (which is pretty darn inexperienced since release, but worked in beta alot) it depends on scouting. I often just rushed to muties with zerg, especially in 2v2. (also depends if you are being scouted...and when)

if they scouted early enough, it looked like I was doing an 8 pool rush, after their probe/drone left the base, I would start gassing, and have the lair up asap, then spire, then make muties.

If they defended at their choke...especially a static defense....it was game over (or a protoss who make zealots who can't do a damn but of good against the muties)

When the spire was up, I normally had up a queen and had already spawned larvae, and had enough gas for 6-7 muties.

But, I have not played online since release, and don't know how much things have changed. I do not know that this would work in the higher levels, if the enemy kept their scout around, well, rushing muties would probably end up being a useless endeavor.

 

For me right when my spawning pool is done I make a queen and wait for 3 larva and 150 minerals and pump out 3 zerglings.
Right when the queen comes out you have enough to start lair.
Next larva goes to overlord because food is at 18/18
Your zerglings are running for probe line.
Even if they die you spawned larva with queen and get out 12 more zerglings to protect or keep attacking if it worked.
In this time get other extractor and 3 drones for it.
Lair should be done and now make spire for mutas.

I usually expand now.

Sometimes I make hydra den because of AA.

I just make mutas and harass worker line and have zerglings and hydras for ground.
Very late game ill get broodlords to help out on ground

 

This can't work most of the time, don't you always encounter toss which wall off their ramp with pylon/gateway/zealot? And even if you get through, 6 lings get taken down quickly by probes.

 

10 drones > Overlord > 3 drones > Pool > Extractor > Extractor ( 2 drones in each) > Queen / Drones. Basically you should have a Pool, 2 extractors, and something I prefer to throw up aswell is a Evolution chamber just because you have the minerals. I'll have 16 drones 4 on vespene and a queen which is 18/18. At the point the queen is done being made you should have enough gas and cash to get your lair as soon as your queen pops. Obviously this build order isn't made for instant ling rush. But you can easily get speedlings and after you've made another Lord can start popping off speedlings. The vespene can be speant on +1 dmg which helps a lot while gathering up a small pool of lings.