A cookie is the only reliable way to determine returning visitors, which is fine if you are setting cookies anyway as part of your page but I think it is a bad

A cookie is the only reliable way to determine returning visitors, which is fine if you are setting cookies anyway as part of your page but I think it is a bad choice to introduce a cookie to an otherwise non-persistent page just for tracking. Fingerprinting is the next most reliable way but raises all sorts of data-retention issues. Maybe it is acceptable if the fingerprints are only stored for a very short period of time (say 1 hour). For my home-brewed analytics system I eventually decided that the trade off wasn't worth it. I just count page views rather than visitors. I know it isn't industry standard, but I don't care and nobody in "the industry" is going to trust self-hosted analytics for anything anyway.