Just wanted to reiterate that A-M gutter guards can be installed over both types of fasteners: the kind that is sold in Home Depot and Lowes (1) as well as the kind that is sold on Amazon (2).
I used both types to repair my house's gutters over the years. Admittedly the first type of fasteners protrude up a bit more especially if you over-tighten them (they are width"“adjustable), so the aluminum panels end up having small bulges over some of them, which is only a cosmetic thing and would only matter if you could see your gutters from a second floor window provided you are a perfectionist...
So, looking back I would use only the second type fasteners (non"“adjustable), in case you need to do repairs on your gutters before installing the panels. The second type fasteners are better designed, stronger and cheaper (on Amazon).

The product is well made in USA. The sharp stainless steel screws purchased as a bundle perforated the older existing aluminum gutter edge very well. I dropped the torque setting of my drill/driver to about 5 to just tighten the screws but not to strip them out. The already formed holes in the front edge of the guard are a great help in installation. I had to sometimes pull out my slightly bent gutters where ladders were placed in the past and using a ladder stabilizer on the roof of the house worked best for me. When you got the bent gutter to the correct 5 in. size (in my case) it just popped right in place ready to be screwed down.
I did not put a screw in every single hole although I sure that would be best. I made sure the ends were screwed down and every other hole was secured as well and it was very tight and strong in appearance and feel. I believe the roof will be gone as well if something rips this guard off. I will buy this product again if I need more length. We have oak trees that produce what I call wiggles each spring. Nothing may adhere to this surface at all. But I really will not mind if I have to gently brush or sweep off the surface once a year.

I got a quote on a gutter install and decided I would skip the install of a gutter guard and install a Gutter brush myself. (Of course, I'm sure I'm in the majority who gets an upsell to do the roof after the salesman checks things out.) I researched a little and I came a cross these Amazon Recommended A-M Gutter Guards, which were $100 cheaper than the Gutter Brush, and, more importantly, were designed to eliminate the need for annual cleaning for most people. I knew it was going to be a little more work having to screw them in, but the long term rewards would make it worth it. I really don't like going up on a ladder, and my yard is uneven making it all that more difficult. Plus, I'm getting up there in age at 67, so I want to go up there as little as possible.

My original plan was to install these while on the roof, but it was really hard to see what was going on in that position. The first section I tried would not go in place. So, I moved the ladder under the gutter, and the problem was that the roofers forgot to screw in one of the gutter mounts. I could not see that from above. So, at that point, I decided to do the whole job from the ladder.

Everything, for the most part, went well. I went left to right, front of the house to the back. The final few feet of my gutter were a little tight for some reason, so I had to cut down the width of the gutter guard to get it to fit in place. The aluminum is easy to work with and I was able to cut it to size with tin snips. It was getting a little hot out and I was pretty exhausted, so I'm thinking I might give it another go at another time. I have plenty of spare panels that I can work with, AAMOF, I think they give you a few extra panels, which is nice.

I ordered these on Saturday, the day after my roof and gutters were installed, and Amazon delivered them to me on Sunday, with the screws I ordered, when both of these items were expected to be delivered the next Friday. Very nice of them! Since I do not have prime. So, I was able to start work at 8:30 AM on Monday, Labor Day and I was done at about 11:30 AM.

I was prepared to use the A-M Gutter Guard Screws and magnetic Driver just to use the recommended product. But, apparently they are out of stock since it would have shipped a week later than the gutter guards. So, I followed some of the recommendations here in these reviews and ordered them as well.
"120PCS #8 x 1/2'' Sheet Metal Screws 410 Stainless Steel Hex Washer Head Fast Self Tapping Screws with Screwdriver Bit Silver" https://www.amazon.com/dp/B0BWN392S9?ref=ppx_yo2ov_dt_b_product_details&th=1 (Includes a 7mm magnetic driver which works great.)

Overall, I highly recommend these gutter guards. They are strong enough for whatever Mother Nature may throw at them and flexible enough to be reworked for the areas that might not be exactly as expected. And, they are cheaper than Gutter Brushes, which have to be cleaned out annually (at a minimum). At my age, I'm hoping I can avoid ever having to go up on a ladder again.

Pretty slick way to protect gutters. Measure width before ordering. Easy install

I've been struggling with Pine needles and leaves in the gutters. These installed super easy and work well. Needles still collect on the top of one of the gutters, but are easily blown off with a blower. Nothing is maintenance free. I recommend.