I sat through the Wood County Master Gardeners conference 2 weeks ago and one of the speakers was Prof Bill Knoop who developed the "Don't Bag It" program for the Texas Extension Service. His recommendation was to mulch all grass clippings and never pick them up. He said that mulched grass clippings didn't contribute to thatch and returned much needed nutrients to the soil.
So, seriously think about putting a mulching kit on your mower and and save yourself the time, money and effort of picking up those clippings. I have a 4 acre yard that needs mowing every 5-7 days and I haven't picked up grass in the 10 years I've been here. Never had a problem with thatch. With the mulching rings and blades on the mower the grass gets chopped up really fine and blown back into the yard. The only downside is that you have to mow at a slightly slower pace but it is still faster (and easier) that mowing and raking.