I'm not exactly a newbie but I'm still in the novice phases here... I've always brewed 5-gallon batches from kits or CloneBrew recipes and I've NEVER used a blow-off tube because I didn't know they existed until recently--I've always just use an airlock. I guess I've just been very lucky that I've never had a leak or explosion.
The question is, how do you predict *in advance* whether you will need to blow off? As in, *before* the mess? Are there certain kinds of yeasts or combinations of ingredients that build up more pressure than an airlock can handle?
My fermenting "closet" only has a vinyl accordion door so if I had a leak or popped lid I would not only be cleaning up wort, but also two alcohol-poisoned cat corpses (or at the very least, cat vomit in every room of the house).
P.S. I do my primary fermenting in an a plastic bucket, secondary in a glass carboy.