Relation of cache and fingerprinting in assets pipeline in rails

My learning I know the purpose of assets pipeline that they minify, concatenate and compress assets. In production environment we compile assets our self by

rake assets:precomiple

and all sprockets add MD5 hash with their name and they all place in cache and when content of file change MD5 also changes.

Against each request instead of compilation all assets get through cache and time saved.

Want to know

1) If cache time expire then what happen meanz we cant precompile assets again then form where assets get?

2) If we change in a file then it upload it then cache automatically update that that or it is necessary to precompile first?

3) What happen in development environment in it how cache work with assets and for every every request?

If anybody have tutorial or a blog about or info about that kindly share.