I mean, I used to install glass without cleaning the edges. Idk, I thought it was no big deal. But on a job last month, the sealant failed because of grime. I had to pull out the whole pane and start over. Now I always wipe down with rubbing alcohol before I apply anything. It takes a minute extra but stops problems. My work has been way better since I started this, like on a recent bathroom mirror that held up perfect even with steam.
I was cutting some heavy glass for a storefront and my old cutter just slipped. Ended up with a jagged edge and had to order new glass, which set the job back. So I bought a better cutter and now my cuts are clean every time. It cost more upfront but saved me money in the long run. What cutters do you guys trust for thick glass?