Vacuum Lines <-- info needed

[84 500SL Euro]

My cars, [see signature], have a mix of black rubber connectors and smaller diameter translucent plastic 'runs', mainly though not exclusively, over the hot areas of the engine but due to the age of cars and ignorance of when, if ever, they were replaced, I'd appreciate comments regarding the following:

1-what are the inside & outside diameters of the 2 tubing types

2-of what material is the, black and translucent, made

3-where can a full written description of these lines be found

4-any recommendation as to vendors

5-what's the going rate for these items and any suggestion as to purchase process to minimize cost

6-how often should these lines be replaced

Thanks once more for all the help,

Courtney