[riffraff]

personally, I know I can use search and replace, but <ctrl-n>-n-n-c-replacement[0] is easier on my mind than the search&replace alternative

[0] I've been using vim-multiple-cursors for years, it's abandoned but still works ok most of the time.

[bspammer]

Do you know about *? It puts the word currently under the cursor into the search history.

So you can do *ciw, type your replacement, then n.n.n. to do the rest.

Obviously LSPs are more powerful though.