For a Web or mail server, it's very necessary, so that users will have uninterrupted access.
For a workstation, probably the only real benefit is being able to access your machine remotely.
I'm not sure if your IP really has any effect on your search engine ranking or possible penalties.
Good luck.
Most hosting companies are strict about who and how many IP's they pass out. If you are on a cheapo $10 a month host, you will likely have a hard time. Each host gets alloted a limited block.
Needing an SSL cert is a good excuse to have them issue you an IP.
It is generally accepted that a dedicated IP does improve your rankings.
Then I'd say the general knowledge is incorrect. There's no boost coming from a dedicated IP that I can detect and I examine many, many domains, IPs and SERPs every week.
The only advantage I can see is that it's harder for someone else's email spam to get your domain on a blacklist. Even then, blacklists are not usually looking at ip addresses but at domain names and mail servers.
If you are using high risk SEO methods, then a dedicated IP "might" help keep you under the radar for a bit -- but I did say "might". There are so many things that can trigger a penalty or a hand check. Heavy cross-linking, even between separate c-classes, is one big trigger. If you've got some monster domain network rolling on one c-block, then you certainly might want not to host a brand new venture at the same address. It hurts a lot when everything can go down the drain in one fell swoop.
A dedicated IP is not a bad thing, far from it, but it's been elevated to a nearly religious status by some. It's just not all that. People have been getting obsessive and a bit crazy about them.
