Best time to use boost?

I normally use my boost at the start run out around half way through the race(100%) the people who use boost at the end either get past me or only just behind. IdI like to know if it's better to use boost at the end or at the start?

I normally use most of my boost on the lap just before  I pit as the car is lite or if I'm near the car in front ready  for the drs zone

Yea similar to what Wayne said.

I try to save my kers for end of the race, but also depends on track. If I can use some to make an overtake on a track where overtaking is difficult that can be a strong advantage having clean air.

Then little shots here and there for drs zone management. Closing gap to get it, increasing gap to deny it.

I agree

I think KERS is a multiplier to performance compared to a solid additive meaning that you get the most out of it when you use it when your at your fastest, basically don't use it when you've just put in 30kg of fuel wait for it to burn off abit is what I've noticed.

As for whether to use it in slow corners, on straights or coming out of corners to get the most KERS to M ratio? I think using it coming out of corners is the most efficient but I've seen medium corners work well and abit on straights to jump someone maybe alongside DRS perhaps, so theres less of an issue here.

Aim to use as little as possible so if your 1.2 secs behind and want to stay in DRS don't go mental using loads to get to 0.5 when you only need to get to 0.9, its hard to master but very benificial and if your fighting another car half way through the race and you have 50% left and him 70% that means he has the advantage, hence why people like to save asmuch till the end of the race.

It's different for each track, and even with multiple races on the same track the situation can be different, one race the pack can be all together and in another, you have multiple groups all split from each other or whatnot.

Each track has different characteristics, influencing factors such as how close the cars are able to follow each other, to the strength of the DRS straight. You'd ideally want the best boost tactic for each track, 'best' being a nebulous word at best, and while most of us would give tips such as save as much boost for the end of the race, best to use it when you're just coming out of corners and whatnot, you're also encouraged to do some experimenting to see what works best for you.

But whatever your boost tactics for each track, a good rule of thumb to have is to always have some boost left for the end of the race. Having boost keeps your options open, so unless you're super confident in getting a certain result or need to leave early, never run out of boost until the race is over.