Banks are usually worries about judgements when it comes to collections.
Say you have an old account that is for 5K. If they get a judgement against you and get a withholding order, they can take up to 25% of your check or so towards the order. Banks worry that if something like that were to happen, you would default on the loan, so they like to see items that are large enough to be worth the creditor's time, and recent enough to be within SOL to be paid. Older ones like yours, or small ones are usually ignored but may require a letter of explanation.
One thing to beware of though is if these collection companies have filed irreneous credit reports on the file if it is past the 7 years. Sometimes they do that to try and force a settlement, especially if they see you app'ing for a home loan as they know the bank may require it paid. You want to make sure none of them have done that, and if they have, you get it removed prior to applying as an UW will probably require it taken care of.
