Joyous, every farmer used to have a junk pile where he went when he needed a piece of metal or a length of hose or a handful of screws. It saved him a lot of money as well as time because he didn't have to go into town to buy a part that he could make right then and there.
I'm probably the last person to give advice on this subject, because I believe in having a "junk pile" of sorts regardless of your living circumstances. There does come a time when too much junk overwhelms. I think the key is whether the junk is usable or not.
Making up rules like how long to keep it or how much to keep might seem like they keep things under control, but in the end, common sense does better. Do you have more than one of an appliance that may be needed for repairs? You may want to get rid of the worst one. Do you have room to store those appliances, or could you make better use of the space by storing something else there? I'd keep asking myself things like that.
(This from a person who is making a real rag rug right now and who saves string from bird seed bags....