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.
ys<motion><character>
For ys, you can remember as "you surround".
Surround the word hello with double quote
yse" or ysaw" or ysw"
cs<current-character><new-character>
For cs, you can remember as "change surround.
Change surround character from " to '.
cs'"
<visual mode selection>S<character>
Select world hello with visual mode and then surround with character ".
veS"
Select to the end of word, then surround with '.
ds<chracter>
Delete a surround character ".
ds"