Hi
@ColinFBMHUservoice open for it here -
https://planner.uservoice.com/forums/330525-microsoft-planner-feedback-forum/suggestions/14704662-op...Would vote to push it up the agenda. Microsoft has given it a response -
'Thanks for your feedback! We’d like to add custom columns to Planner, but don’t have anything planned at this time. We’re working on three big initiatives that are landing later this year (stay tuned!) and will likely start work on recurring tasks soon after. Please continue to vote as we utilize UserVoice heavily to order our product backlog and will adjust regularly if things change!'
Voting on these, you will recieve notifications if it gets picked up. It's a high number of users who have voted here and when you get to this number it is moving in the right direction. Also if you see any Planner AMA's here on the Tech Community, get on them and ask the question again referring to that uservoice - the more visible it is the more momentum is created
Hope that answers your question!
Best, Chris