Best practice for trigger a process definition after a long period of time.

Hello, I hope you are all well. I have a request from my business to update a field on the contact record after 120 days, simple enough, so I thought. My first thought was to create a Process Definition to look for the event and wait 120 days. But I had some thoughts that I wanted to get feedback on. 

  • Does having several process in a waiting status cause issues? 
  • How long can I reliable keep a process in queue? 
  • What is the best practice for queuing PD's after a long period of time? 

I did some searching around but couldn't seem to answer these. Words from your bright minds will be greatly appreciated.