Own IP's: advantages vs disadvantages

I have a few questions concerning whether someone shall or not use a fixed IP instead of a dynamic one, when hosting multiple domains:

1) What are the benefits of having a fixed IP?
Any impact on the speed or performance?

2) In what conditions is it necessary or better to have one?
E.g.: custom nameservers, security reasons?

3) Besides the cost of IPs, what are the disadvantages or problems resulting from using a fixed IP instead of a dynamic one?
E.g.: any problems on privacy or security?

 

 

 

 

Top