How do you update content from a spreadsheet that keeps coming back with changes?

A lot of sites are kept up to date from a spreadsheet someone else sends: a supplier's price list, a listings export, the programme for the next theatre season, a client's spreadsheet. The first import is easy and there are plenty options out there to facilitate that. Following updates are the problem, when the same file comes back with some rows changed, a few new ones and a few missing. How do you go about that? The options I know are all a bit uncomfortable. Re-import everything and hope nothing gets overwritten. Compare the two files by eye. Edit the items one by one in the admin.

How do you handle it? Do you have a routine that works, or do you just brace yourself and click import?

I'm a developer, and I ended up building a tool for exactly this, called Content Uploader. You drop a CSV or Excel file, and before anything is written it shows what is new, what changed and what stayed the same. Next time the same file comes back, it updates the same items. It works with WordPress, WooCommerce and Joomla, and there is a free plan.

It's on Product Hunt on Wednesday, so if something looks wrong or missing, I'd like to hear that too: https://contentuploader.com/?utm_source=producthunt&utm_medium=thread&utm_campaign=launch-day

But mostly I'm curious how you do it today?