How long can creditors report neglagence on my credit?

I have considered filling bankruptcy but I was wondering, how long can creditors report to my credit. I was always told that they can only report for seven years, is this accurate??....i have several items on my credit that are going to be 7 years old next year and wasnt sure if bankruptcy would be the best option for me considering these delinquencies have almost reached the 7 years. Also, if a delinquent acct was sold to a collections company, then do the 7 years start over every time my acct gets sold? How exactly does this work?? A little background; most of the debt is from an eviction, reposetion, med bills, utility comp, etc..only $300 of the debt is from credit cards and my debt totals about $20,000.....thanks for any advice...also, I have not had any negative debt reported w/i the past 3 years or so, what is the best way to improve my fico score....i have heard that a secured credit card helps if u use it and pay it off every month/...thx again