The picture at this link https://drive.google.com/file/d/0B51...ew?usp=sharing
Shows the hot and cold water lines to the washing machine. You can see the two pipes at the top seem to be deteriorating, especially the right one, from mineral deposits perhaps. It's all discolored, the left one has much less. I'm thinking this could lead to a big problem in the future and perhaps those pipes should be replaced very soon? How much cost and time would this normally be?

Those look like compression fittings, and the one on the right appears to have had a slight leak long term.

It is not that bad. The cold water side appears to be slightly corroded. That is most-likely residue from an old small leak. Take steel wool and rub the green corrosion off. Then, slightly spray it with WD-40. That should do

I don't really see any "white foam" on the pipe that would indicate calcification. If there were any, then I would suggest some kind of water treatment system. But I do not think it is the case here.

Hope that helps

Milo

Joe,
White deposits may indicate water with mineral hardness; blue / green staining is usually associated with low ph which in extreme cases can cause pin hole leaks in piping and premature failure of water tanks, water heaters, fixtures, and fittings.
Public water supply systems are monitored and tested often - if you are connected to one, request a report of the waters physical characteristics; if you are connected to a private well, have a water sample tested by a certified lab. A clean fresh water supply is important for obvious reasons - I think it is fun & interesting to know what is in the water we use each day without a thought of its quality...

I agree with Milo, its not too bad. The green corrosion indicates a small leak, possibly an old leak. Remove the compression valves and brass ring, ferrel. Clean with steel wool and CLR. You van try reusing the old ferrel but I'd replace the ferrel and go with a new one to be safe.