I've been loosing my plug for a couple of weeks now, and some days it'll be alot more than others. On those days I'll be in the bathroom many times during the day, and I'll have contractions. The next day, absolutely nothing. Its getting ridiculous. I think its different for everybody.
There's no particular time frame for anyone, things just happen unexpectedly and that's one of the bad perks of pregnancy, you never know when things will happen and what your body is going to do