I cruise around town at like 4k, usually shift in that area too.

I've never seen what I shift at while getting on it, no where near redline tho, maybe like 9-10k or so. Like others said, I don't wanna ride beyond where I'm comfortable. I'm also assuming my rpms, because as others said I go by sound. And I rather keep my eyes on what's ahead even if I'm familiar with the area