If I put an image in a post in this thread, then I can get a list of the IPs of the people who have viewed the thread. Cross refer a few threads, and I can probably isolate your individual IP.
This was actually done many years ago, many people viewed this person to be a scammer as a result. The forum currently uses an image proxy that makes this attack useless.
Only administrators can see your IP address.
The member's table has leaked at least once, and the forum has been hacked multiple times. Your registration IP address and your last recorded IP address as of when the members table leaked is more or less public information now. An unknown amount of additional information from the other hacks is potentially essentially public information as well.
Long-term logs are currently kept indefinitely.
I would advise against this.
Over time, you will inevitably lose some of this information for a variety of reasons, and you can potentially be in legal trouble if you are unable to produce specific information you say you retain indefinitely, especially if you are close to the person.
I would suggest, as an alternative to instead either retain the name of the person's ISP, geolocation data, or truncated IP address (or a combination thereof) over the very long term. This is likely what you essentially will use for things like account recovery anyway and in most instances, a user's IP address will have changed after several months (and to a much greater extent, after multiple years) anyway.