An IP address is a unique number that distinguishes an Internet site or a hosting server on the Internet, so in the event that you have a dedicated IP, it'll be used just by your Internet sites and won't be shared with other individuals as it happens with shared hosting accounts. Provided you have your own web server, you will have a dedicated IP, but you may need additional ones for different purposes. Provided you have an Internet store, for instance, you will need an SSL certificate for it, so as to make certain that the payment info your customers submit will be encrypted and safe. The same is valid in case you have a login form of some kind and you wish the usernames and the passwords that visitors enter to be protected. The SSL certificate requires a dedicated IP address, which has to be different from the one that you already have on the web server. You might also need an individual IP for an app such as a VoIP server, or if you want a slightly better overall performance for a particular Internet site, which may influence its position in search engine results.
