Using Tasker to know if I'm at work for more than a minute
Use Tasker › Wait in the task. When your WiFi near fired, just have it waiting for e.g. 5min, then exit if no longer WiFi near, otherwise continue with your task.

You could also bring variables into play, e.g. setting %STAYATWORK to 1 if the WiFi is still in reach after the wait, and have your other tasks using that as context. In this case, don't forget to reset %STAYATWORK to 0 (or unset it) if the WiFi is no longer in reach :)