I have had 4 to date. My first came without any real practice or prompting; the next was about a year/year and a half coming.

Since I started recording my dreams and reading on LD techniques about two or three months ago, I've had two. They were both short lived though, the first didn't last long and I forgot to silence my cellphone for the second and it woke me up -_-.

More often than not (75% of the time ATM) they come during my afternoon nap, so hopefully if I keep taking the nap I can have them more often!