...This isn't necessarily true.....they will tell you this... (Quoted from Technopunk)
The reason I say this is not because someone told me this, it's because I have direct experience trying absolutely everything else, repeatedly. I know about all the life stages etc... but IMO and from experience, you will spend just as much money doing repeated treatments on your own which may or may not work (and did not in my case). At least if you spend the 100 bucks or so on an exterminator, at least you get a guarantee and if it doesn't work, they will come back to retreat without it costing you any more money. (I don't know if they all offer this, but you should find one who does). Some things are just no worth fooling around with yourself. I've learned that the hard way.