I use a spade and I know someone that does use a shoe knife, but they have much more time on their hands then I do.

I used to edge with a Fiskar hand tool designed for edging, but then I stopped when I realized it's probably better for the grass not to do it at all.

I have Bermuda which puts out runners. Edge by using a small serrated knife to rogue out what has encroached in my beds. And dispose of all of it, bagged at the street. Can't seem to keep up with it, though. Too many handreds of feet to be edged. Do have an electric edger which I use along paving.

Watchnerd, why would edging be bad for the grass? Isn't it the same as cutting it?

"Watchnerd, why would edging be bad for the grass? Isn't it the same as cutting it?"

Not really. You're severing roots and creating a gap in the soil that traps moisture and through which fungus can enter.

Here is a recent is another perspective on asking why we bother:

Here is a link that might be useful: Why do we obsess over edging our lawns?

If one does not edge the grass at the sidewalk fairly soon that grass would grow over the sidewalk and cover it. also many grasses send out Rhizones, Stolens, etc. that cause the grass to grow into planting beds, a place many of us do not wnat grass to be growing, so edging helps prevent that.
A spade usually will cut about a 9 inch width and often much deeper then a knife, or even most of the powered edgers I have seen will and that quite often allows me to forget edging those planting beds for a couple of years.