Also, Slack is not documentation, for all of the same reasons. I'm working with my company now to improve documentation across the organization. We're an old startup (takes a very long time to get to market) and in the past quarter I've led two projects where I've spent weeks trying to answer questions about old code, sometimes finding that the original author is no longer at the company and no documentation exists or the original is still at the company but literally doesn't remember writing the code and no documentation exists. And each time people tell me there are Slack conversations explaining everything ... somewhere. No. Every project, every application needs a design doc before and a user's manual after and they actually need to get maintained.