You can do whatever you need to do, however you need to do it!
There are 8,000 ways to do the same thing. Some make more sense than others, just choose!
The Right Way
Create block or inline contexts for various elements.
Want your <a> element to be a button, make it block or inline-block.
Create complex layouts trying to use just Block, Inline and Inline-Block
Want to create a grid of 3 items DON'T use inline-block.
Want an element to have text wrap around it? Use floats.
Literally anything else.
When exact placement matters.
Should only be used for minor things.
Use when your content's size matters.
Use one one-directional layout makes sense.
Use when a browser doesn't support Gridded content.
Save yourself a headache don't try to use it in a column.
Use Grid when your layout itself should control size.
Use Grid when two-dimensional placement makes sense.
Create a 12-column grid and pretend that it's Bootstrap.
What would you like to see?