Maybe 80 hours total, but then that's it. And then you have speedy skills that can serve you in almost any command line environment. AND vi commands are used in a lot of other places, like man pages and such.
it's an up-front cost, but it's one that you'll benefit a lot from over the years.
I recommend starting with soft plaintext, like a diary. Over time, you can migrate to using it to edit code. My conversion took a couple months, and followed this pattern.
I started by editing plaintext diary files. Then, once I was very use to the in-file navigation, I installed vim-mode on my editor of choice at the time, so I could benefit from efficiencies there, while keeping all the IDE benefits.
Then, I began the process of replicating all of the features I used in my IDE, in vim. that took maybe another month, and was motivated by how painfully un-snappy my IDE was relative to vim.
This is all to say, it doesn't have to be an all-or-nothing cutover. That would be painful and frustrating.
