I have the Leightning 33db NRR muffs that I prefer over plugs; but the muffs headband doesn't rotate like my cheapy Home Despot AO Safety 25db NRR muffs. I don't use the AO Safety much anymore because the cups rotate out of position and therefore don't protect like they should. Since the Leightning muffs headband doesn't fit under my SPF 1,000,000 head sunblock (a.k.a. hats, hardhat), I use them when running my vertical bandsaw, chop saw, table saw, and similar indoor equipment. Very convenient to put on and take off at a moment's notice.
When using the tractors and weed whacker, then I use 33db NRR disposable plugs. I've gotten use to sticking them in my ears, so it's no big deal anymore. I keep a few pair in the 4200's glove box.
I would prefer to use muffs for extra debris protection with the weed whacker because unlike my neighbors who think shorts, short sleeve shirts, a ball cap and sandals is appropriate attire; I wear long sleeve shirts, full length jeans, leather gloves, a hard hat with full face shield, and a dust mask if it's a real dusty day. I had a pair of hard hat mounted muffs rated at 28db NRR; but they never fit properly, made the hard hat even more top heavy, and when the Chinese plastic finally broke, they went in the trash. I've had tumbleweed debris hit my hard hat and it makes quite a thunk when they have matured to the woody state. I've even thought about a set of chaps because a couple of rocks have been flung into my legs a couple of times. That sure smarts for a couple of minutes. I'm glad I wear all the extra stuff because when I get done, I have so much vegetation debris on me from head to toe that I feel like I worked as a salad maker.
Regardless of your hearing protection preferences...just wear something!