Say you don't pay a telephone bill and it goes to collections - how long does the telephone company have to send it to collections - I heard it was 3 yrs from the last day of payment.

They may send it ( or sell it) to a collection company anytime, 1 year , 3 year, 10 year even 20 year,

You will always owe the debt and they can send collection letters and try to collect as long as you live.

The difference is how long they have to file in court for a judgement. This varies by state if you live in the US,