I’m using EventStore to record clicks, the application that gets the clicks appends it to a single stream and another application generates reports.
Is there any hard limit to how long events should last or any performance issues with keeping events for a long time?
Ideally I wan’t to make sure they are there for a good few years.

You havn’t mentioned how many of these you have but practically no (that is the point :)). If we are talking even 100s of millions it should not be any problem.

About 2,000 a day maybe so yeah a long time before a few million, thanks!

We know of a production db doing similar things > 10 tb at this point. If reading a lot ram and/or fast disks are useful depending on your reading patterns