Thatch isn’t dead material, it’s a live, poorly formed root system which is too tight and too close to the surface. It’s caused by shallow watering, and by watering during the day when the water evaporates away quickly. Mulching actually helps prevent thatch by allowing water to soak in a little deeper and preventing evaporation.
If you do have thatch, then yes, cutting it apart will help alleviate choking. But you have to change how you water if you want to keep it from coming back.
I don’t water at all, it survives on rain water and morning dew alone. I guess that mean my lawn will have thatch and for the most part, I’m OK with that.
While there are plenty of people saying what you’ve been told, the research and asking around that I’ve done says that these people are either:
No, rain penetrates deeply. You should be fine.
I never bagged, but my wife started insisting. I just empty the bag in the woods, not really for my own compost needs. It’s not a big hassle, but we have a small yard
I picked ‘other’ because there’s no option for ‘Bag and haul to rubble site yourself’.
I’ll bag it if it gets too long, but usually I just mow it with riding lawn mower with the side discharge. Therefore, in those instances, it would be ‘none of the above’.
I selected “Mulch in place”, but my new mower allows for both simultaneously. It’s able to send a variable percentage to the bag, which I do to please my wife. She gets to see me empty the bag from time to time and I get to mulch the majority.
Mulch. A sharp mulching blade will not produce clumps or long blades of cut grass; the mulching blade cuts the clippings nice and tiny. We have a full acre and if I stopped frequently to empty the bag/s, it would take hours to finish. Once you start leaving long strips of clumped grass, it’s time to sharpen your blades. Every week I’ll rake up a small pile of clippings and throw them into the compost pile, but otherwise I leave them where they lie and you can’t even see them.
It usually takes a while for thatch to build up, and a dethatching every 3-5 years is all that’s necessary to eliminate it.
All you ever wanted to know about thatch.
http://plantscience.psu.edu/research/centers/turf/extension/factsheets/thatch
I love the fact it is written by a “Professor of Turfgrass Science”. That’s a thing? 
I voted for “other,” simply because my answer is a bit of both.
We have 2 lawn mowers, one that is a big mower - 48" deck, (is “deck” right? I think so…) it mulches and my boyfriend uses it to mow the back and side yard. The front yard is smaller, and he uses the mower with the bag to mow it; it has a smaller turning radius.
I take the clippings from the bags and either put it into the compost, or bury it directly into the vegetable garden - between the plants, in order to let the worms at it, and it gets tilled in the next spring.
As far as the grass quality goes, we have lived here 3 years, and I cannot tell any difference between the front, side, and back yard, so I’d have to say it doesn’t seem to matter much.
I have been told to put a couple bags of grass clippings over my flower bed in the fall to enrich the soil, (and insulate the roots of the perennials,) but I tried that with tree leaves this past fall, and still had to rake them out this spring. I understand the grass clippings are smaller, and would decompose faster, but if anyone can tell me if I would have to rake out the excess in the spring, I’d appreciate it. 
I believe grass clippings are higher in nitrogen, so that right there might be a plus…
SMALL clippings. The smaller, the better. Run the mower with the bag, over the leaves, dump the bag back into the yard and mow/bag them again. They should be now be small enough to rapidly break down in the flower bed.
If you chose to use grass clippings, start with the mower deck at a high(est) setting and reduce the height 1 setting for each repeated cutting. You’ll produce small, easily degradable clippings. Yes it takes time but you’re outside in the fresh air and getting some sun.
I now use a Toro Ultra Blower Vac model 51599. It has a metal impeller which chops up small twigs and survives the occasional rock strike. And it turns dried leaves to dust very quickly. Plus, it blows at 235 mph and sucks 390 CFM. It’s a beast.
http://www.consumersearch.com/leaf-blowers/toro-ultra-blower-vac-51599
Decomposition could depend a lot on your region - moisture and temperature both play big roles.
Leaves will decompose a lot faster if you’ve done some mulching of them first. Whole leaves that are just raked up tend to survive better in my garden than when I mow them up and dump the shredded leaves into the garden. Grass decomposes even faster than leaves.
One option you might consider: instead of raking the leaves out in the spring, leave them in place and cover them with mulch or bark. This will let them finish decomposing in the warmer weather.
My mower mulches but I’m usually pretty lazy and the grass gets tall, so I use the side discharge.
The blades must work well because I still don’t get THAT much clumping despite my laziness. It’s more of a “blanket” of clippings in most areas, so it is at least distributing it well enough.
It was a $380 push mower, so I’m not surprised that it does a good job even with side discharge.
I mulch in place because my current home doesn’t have a compost pile. Once we move and I build a new one, I’ll start bagging and composting again.
In addition to the PSU citation already listed, Michigan State has done a lot of great work on this topic and their white papers are available online as well.
The latest research shows that not only should you leave your grass clippings in place but you also should mulch your leaves in place. The important caveat, however, is that you need to get everything down to dime size pieces or smaller. In Florida we had some annoying tree whose leaves just couldn’t be picked up by the mower so we still had to rake them, but since we moved I haven’t touched a bag or a rake.
I mentioned to people here at work how 4 of the answers in this thread were “I bag, but only because my wife makes me.” We’re now curious about this gynocentric lawn bagging fetish. At least one person proposed that it was simply a way to keep their husbands out of the house for as long as possible, but I’m wondering if there’s more too it than that. Any theories?
My guess is it’s a holdover - their fathers / ex-husbands / they themselves did it, and it’s “how it should be done.” That, or they think mulching creates the unsightly clumps of grass, and they don’t like how that looks. (Nor do I, so I can understand that mindset, even if it’s not correct.)
Thank you very mulch.
Mine wants me to bag because she believes it helps with the kids not tracking in grass when they come inside.
That was going to be my suggestion. Little bits of grass in Summer, little bits of dead leaves in Autumn, little bits of x-mas tree needles in Winter, little bits of Easter Basket Grass in Springtime, these are the bane of a housewife’s existence.