Stockbook, Mounts, Hagners, Stocksheets - I Am Confused

Greetings All,

I am pretty confused today, after I attended a small get together of stamp collectors of my city. And I would like to put forward my questions that I have in mind for some expert opinions here.

A background of my collection: I collect Mint Non-Hinged stamps of my country (India) and owing to the tropical weather here, it is hard to main the stamps.

1. What is better? A stockbook or Hagners?
2. If a stockbook is used, and stamps are kept inside mounts is it better than keeping the stamps in Hagners?
3. How often a stockbook should be changed? 2 - 3 yrs?
4. How often mounts should be changed?
5. Do chemical leech in from mounts and hagner strips into the stamps over a long period of time - 5 yrs? I mean quality mounts and hagners made by Lighthouse, Prinz etc.

Appreciate your inputs.

Regards.