Apropos of your last sentence, I brought up institutional knowledge when chatting with
@johnson86-1 in another thread earlier this week.
As long as you train and communicate with people, provide them with the info they need to do their jobs, and be available when and if they have questions, things should be okay.
My former office has had significant turnover this past year.
A co-worker left just before my former supervisor moved up a level to upper administration.
People hired for those vacant positions arrived shortly before I made my move.
I did some prep work training folks, introducing them to people they needed to know, and making sure procedure forms were updated.
I had phone calls and messages from them the first couple months after I left but they’ve become more comfortable as they’ve become familiar with my previous duties.
I don’t really expect them to ask me any more about work-related issues they have but I’ll still help them if needed.