A number of doors in our house, due to age are having some annoying issues we want to be resolved. Some of them are long-standing issues, others are fairly new. 

1) Most of the door handles open/close mechanism have become "rough", they seem like they are "grinding" and are very loud. Could be a case of lubrication, but I am wondering how long these mechanisms last and if we may need to replace either the mechanism completely, or better to consider replacing the entire door. They are lightweight construction so possibly reasonably cost-effective to replace entirely. I suspect that may mean replacing the wood on the jam? If it's lubrication is CRC the stuff? Is it straight forward to get lubricant where it needs to go, any tips would be appreciated.

2) The entrance to our lounge is 2 doors which close in the middle. They both close using a roller mechanism and since day one, if there is a draft in the house, they rattle. I have reached breaking point as the ratting is driving me insane and I want to know how I can get a better mechanism and who I would hire to do this and potentially look at the issues? I assume builder? Anyone got any ideas on a better mechanism please? 

This is what's on the top of the door:

This is the fitting in the jamb

Thanks!