Need info on deployments of access-lists in production networks

Hi Folks,

For an internal practice I need some information regarding implementation of access-lists in production networks :

1. Where access-lists are applied e.g. on edge routers ?

2. What all protocols are blocked e.g. telnet, peer-to-peer ?

3. What points are considered while configuring the ACLs ?

4. How frequently the ACLs are changed in production networks ?

5. How ACLs are used to prevent from DoS attacks etc. ?

Thanks

Ratnesh