[General] using similar to/similar to that of while making comparisons

[Aamir Tariq]

His handwriting is similar to mine.

My hand writing is similar to his?
My hand writing is similar to that of his.

My hand writing is similar to John's.
My hand writing is similar to that of John's.
My hand writing is similar to that of John.

I am a little confused about when you guys use "that of" while making comparisons between possessions or traits of someone.

Can you guide me in this regard?

Regards
Aamir the Global Citizen

 

[GoesStation]

Handwriting is one word. That of is a way to avoid repeating an article and a noun: My handwriting is similar to that of John means the same as My handwriting is similar to the handwriting of John. In your sentence, either of those options would be unnecessary. Just write My handwriting is similar to John's.

Note that you can't write that of John's. The apostrophe makes John possessive, which renders that of redundant.