My twins started to work. They are 18 and they do not pay any household bills, as they are saving money to buy a car. Should they file or should we include as dependents?

[BobinCT · Accepted solution]

Both!  If they still live at home you can claim them as dependents.  But if they had any income taxes withheld or earned over 6050 or earned over 400 of 1099 or self employment income then they should file, also, being sure to indicate that someone else can claim them.

You never put their earnings on your return.