Locks that work

Are you interested in the advantages of a superior cylinder in your locks such that you could have a D-lock for portable security and a chain & padlock back at home, and maybe a third lock on your shed door, with all locks on the same key ("Keyed Alike" in the jargon)?

I'd never even thought of this... How far could you go with this, could you have the same key for your house, padlock and bike locks?!

Would it lesson the security of a double lock of both locks had the same key?

Also I wonder how much it was cost just to be carrying around three or four less keys?

Also ga2g, is there a reason why none of the folding locks are mentioned? Like the abus bordo? I don't have the abus but have one like it that i find useful.