I started in January 2003 and I'm still absolutely nowhere near completion. As a student you have the advantage of plenty of spare time and the disadvantage of usually being cash-challenged. I know that I spent the majority of my time as a student in the pub, or sitting at home smoking weed. No regrets as I had a great time, but when I think of all that time that could have been spent productively...
I was fairly confident of finishing the PPL course in about a year. I work a fairly cushy shift pattern - two 60-70 hour weeks followed by a week off. When I'm at work, that's all I do - there just isn't the time and energy to do anything else. The week off, you would think, would be ideal for getting some consistent flying in. It's surprising how often you have 2 weeks of seemingly perfect weather followed by a week of low cloudbase, how often there are frontal systems that arrive just at the hour you've booked your lesson, and how often there are seemingly nice days that are in fact hazy and unflyable.
In October, I had appendicitis - a month off work and a month off flying. Since then, my time off has been sparse. The weeks off have evaporated covering other people's holidays and sickness. This week is the first proper week off I've had since November and I've come down with 'flu. The first time I've had any kind of cold or 'flu for three years, which serves me right for gloating when other people were ill. In short, expect some setbacks and try not to be too disappointed when it doesn't all go quite according to plan. I certainly didn't reckon on a 6 month layoff, but it's happened.