Vim surround with
If you have Vim surround with plugin installed, you can use a powerful command of surround with to add or remove character around a word.
Add surround character
For ys, you can remember as "you surround".
Surround the word hello with double quote
Change surround character
For cs, you can remember as "change surround.
Change surround character from " to '.
Surround with visual mode
<visual mode selection>s<character>
Select world hello with visual mode and then surround with character '.
Select to the end of word, then surround with '.
Delete surround character
Delete a surround character ".