And so / too Shortening a repeated verb in a joined clause

And…so

FULL CLAUSE	SHORTENED CLAUSE – AND SO
And can be used to join two independent clauses.  (Each clause has its own subject and verb; each clause can stand alone as a sentence.)	After and the main verb is not usually repeated. SO + the auxiliary verb is used. The subject comes after the auxiliary verb.
I am five today, and my cousin is five today.	I am five today, and so is my cousin.
My brother has a new toy, and I have a new toy.  (present)	My brother has a new toy, and so do I.   (American English) / have I.  (British English)
My brother is going to get a new toy, and I am going to get a new toy.  (BE-future)	My bother is going to get a new toy, and so am I.
My brother got a new toy, and I got a new toy.  (past)	My bother got a new toy, and so did I.
My brother should say "thank you", and I should say "thank you".  (modal verb)	My bother should say "thank you", and so should I.

*Use be for stating age, not have. See stative verb.

And…too

FULL CLAUSE	SHORTENED CLAUSE
And can be used to join two independent clauses.  (Each clause has its own subject and verb; each clause can stand alone as a sentence.)	When and joins two independent clauses and each clause includes the same verb, the main verb is not usually repeated in the second clause.  The auxiliary verb and too is used instead.
My brother has a new toy, and I have a new toy.  (present)	My brother has a new toy, and I do too.   (American English)
	My brother has a new toy, and I have too.  (British English)
My brother is going to get a new toy, and I am going to get a new toy.  (BE-future)	My bother is going to get a new toy, and I am too.
My brother got a new toy, and I got a new toy.  (past)	My bother got a new toy, and I did too.
My brother should say "thank you", and I should say "thank you".  (modal verb)	My bother should say "thank you", and I should too.

But…not

CLAUSE	SHORTENED CLAUSE
But can be used to join two independent clauses.  (Each clause has its own subject and verb; each clause can stand alone as a sentence.)	After but, the main verb is not usually repeated.  The auxiliary verb is used instead of the verb.
My brother has a new toy, but I don't have a new toy.  (present)	My brother has a new toy, but I don't.  (American English)
	My brother has a new toy, but I haven't.  (British English)
My brother is going to get a new toy, but I am not going to get a new toy.  (BE-future)	My brother is going to get a new toy, but I am not.
My brother got new toy, but I didn't get a new toy.  (past)	My brother got new toy,  but I didn't.
My brother should say "thank you", but I shouldn't say "thank you".  (modal verb)	My bother should say "thank you", but I shouldn't. / don't have to. (shouldn't - not advised / don't have to - not required)

   Also see neither and aither

Common Mistakes

ERROR	FIX
*My brother has a new phone, and so do I too.	My brother has a new phone, and I do too. / and so do I.  (too is unnecessary)
*My brother has a new phone, and I too.
*My brother has a new phone, and I also.	My brother has a new phone, and I also have a new one. (Use also with the full clause.)
*My brother has gotten a new phone, and I have too.  (present perfect tense)	My bother got a new phone, and I did too. / and so did I. I have driven to Disneyland, and he has too.  / and so has he. Use simple past tense when mentioning source. reporting source   The present perfect tense is used to emphasize time duration / experience.

*Yellow highlighted words are examples of incorrect usage.
"and too"