There's another
${HOME}/docs/

tl;dr - Second option usually.

I think a huge part of shell programming (besides recognizing when anything more maintainable will do 😂😂😂) is trying to allow others who aren't as familiar to maintain what you've written. Shell is full of pitfalls, not the least of which is quoting and guaranteeing how many arguments you pass to commands and functions.

To me, the whole point of quoting here is to be crystal clear about where command arguments begin and end in spite of variable substitution. For this reason I usually go for the second option. It very clearly describes how I'm trying to avoid a pitfall by wrapping each argument to find in a pair of quotes: in this case, double quotes to allow variable substitution.

Sometimes it's clearer to use the first approach. For example, if the constant parts of one of those arguments contains a lot of special characters, it may make it clearer to use the first approach with the constant parts wrapped in single quotes.

But even then there are more clear ways to create a string out of other strings. For example, the slightly slower, and more verbose use of printf and a variable, and then using that variable as an argument...wrapped in double quotes since it could contain special characters.

First one has the pitfall of a space at the end of the variable still causing it to fail.

https://www.shellcheck.net/wiki/SC2086

Bash has the worst syntax rules I have seen, and the fact that you can do both of these doesn't help.

I am probably going to switch to fish for any scripting, Python would probably be better, but it seems to be much more complicated and I am too lazy to learn it.

I would've answered but I'm blind now /s

find "${HOME}/docs/"

You want the full path in quotes so that paths with spaces are handled properly. Brackets are good practice when concatenating strings.