This is done in order to keep the grocery vocabulary tidy, as explained here: Why can I not add a grocery name?

For a wish list, you can set the expiration (due date) for the list. This is intended to be the planned date for the event, e.g. a persons birthday or date of a party someone is arranging. Only the list creator can set the expiration / due date.
Once the expiration date has been reached, the list creator (admin) will be prompted if items on the list should be deleted, marked as bought, or a new due date should set.

Note: If you reuse the wish list for a new event that is within 6 months of the old event, you will se items marked as purchased on the list. If you arrange frequent events, you need to create a list per event to avoid this. The reason why this happens is because the list keeps showing bought items going 6 months back in order not to reveal what has been bought or not.

No, there is a 1-1 relationship per user for an item name and a category. This applies to all list types, so e.g. milk will belong to Dairy for a grocery list, and the book title “Inferno” for a collector list can only belong to one category e.g. “Fiction” or “Dan Browne”.

If you have Grosh Premium, you can turn on Live update in the app. This ensures your currently selected list gets updated even though it is currently closed. On iOS this includes the number shown on your Grosh icon (the so-called badge).
If this is not working, here’s a tip for you: This feature only works with one device per user, so make sure you’ve only enabled it on one device. For instance, if you have a tablet and a phone, just enable it on the device you bring with you. Typically your phone. This way, the list is updated when you bring it to a location without network coverage.

Yes, if you’ve added a grocery via barcode scan, the system has sufficient information to show the correct associated image. This is due to the fact that users typically do not agree on what e.g. “milk” is, and therefore also not on what image should go for that item. 

A barcode identifies a special variant of a grocery, as they are unique across different brands and packages sizes. Therefore Grosh knows which image (and other variant information) to show when you add the item using the barcode.

All grocery items in Grosh are shared across users, so the system gets smarter as more grocery items are added by users. To register grocery information for a barcode, you can scan the barcode and add the item to your list. Once that’s done you can edit the information, e.g. add a missing image or add a missing package size.