Sharing a spreadsheet, carefully

We use spreadsheets, a lot.  There’s one in particular that we share and it’s a bit of a dance when multiple people need it in the same day.   We’ve been careful and haven’t had any version control issues or things like accidental sorts on one column but not all columns.   We have built in some data validation, I like it when key cells turn pink telling me it’s a duplicate.  That means some of the data I need is already there.  So far the amount of data is manageable, there’s very little duplication in the content – just those rare pink cells!  Filters make it a breeze to find the records we need.  There’s nothing pushing us to consider a more robust solution now but who knows, sometime in the future we might need to look at moving to a database.  What’s tipped you from spreadsheet to database?  Any hints to share?