Turf experts all agree, if you regularly mow your lawn, you should let your clippings drop back to the ground. Because clippings are 90% water they readily break down into organic matter that feeds the soil and improves soil texture.
In dropping your clippings you are also reducing the need for lawn fertilizer. Therefore you can reduce the total amount of fertilization by 25% because the decomposing grass clippings break down and add fertility to the lawn. Over time you will notice that your lawn has better water holding capacity and a general increase the overall health of the lawn.
Of course, you should only drop clippings when you mow regularly and don’t remove any more than 1/3 of the total length of the blade when you mow. If it is longer than 1/3 and the mowing interval has been more than a week, then it would be a good idea to pick up your clippings.