Can someone recommend me a good mechanical pencil?

[lazyfortress]

I'm in AP calculus this year, and we're taking a crap ton of notes. My generic Bic mechanical pencils aren't cutting it, as they keep retracting under pressure.

I write hard (not too hard). I was thinking about buying one of those $20 Pentel drafting mechanical pencils, as they last very long. I'd probably cry if I lost one though . I've lost 2 mechanical pencils so far out of 4.

Anyone got any good suggestions?

[crazybubba64]

Pentel stuff is solid. Definitely the way to go.

[Marcin]

I do not use pencil but long time tried many pens and Pentel is what I currently use. Great quality for not high price.

[wren4777]

I use the Pilot Rexgrip 0.5. I generally tend to go for cheaper/more disposable stationery though, so YMMV.

[svmlegacy]

I use a Pentel P207. If you're an extremely hard writer you may want to bump to a 0.9mm lead (P209). Totally 100% Worth the money, especially if you're going to do drafting/mathematics often.