Do what ever you want. For most people, having a 2 pattern wide path is ideal for them because it's wide enough for people to walk/run freely on them without crushing flowers. I've seen some towns where one part of town is 1 pattern wide, another is 3 patterns wide, and the rest is 2 patterns wide.
Mine at first used to be 3 wide but then I felt like it was taking up too much space so I made it to 2 wide for my main paths + 1 wide path for other areas.
I have 1 wide with a different pattern on each side to create a border, but it really depends on where I am when creating the path.
I created quite the mini town in my main plaza so it's quite wide there. Though can't wait for snow to finally hit so my snow path doesn't stick out like a sore thumb. XD
My main path is two patterns wide. It runs around my whole town.
But there are some areas with paths that are 1 or 3 patterns wide. I like that you can place flowers in the middle of the 3 pattern wide path! It looks soon cute
My main paths are 2 tiles wide except near the train station where it's 3 tiles, but it goes back to 2 tiles. I also use 1 tile paths for smaller areas and such.
I use 2 tile paths, and I find that the most useful as bridges are also 2 tiles wide. I also find 1 tile too less and 3 too much, so 2 is a nice in-between choice.