How Long Should Facial Laser Treatments Take to Work on Average?

I have been taking facial treatments for about 4-5 months now (every 3 weeks) and i think its shown minimal results if none at all. This last time i am waiting 5 weeks between treatments and this morning showed hair as normal growth, so i tweezed the hairs out. Should i have waited and just trimmed again and again. I have dark hairs, but very stubborn hairs. How long should i have to wait to know if it's going to work or not? thx