The maximum amount of items that can be claimed from the feeds is 30, within a 12 hour window. So you will receive the  “You’ve accepted too many rewards” message if you attempt to collect more than 30 posts in 12 hours. There are no different categories of items like water or baby bottles or even Grocer Points; they are all in that 30-in-12-hour limit.
This limit applies to both the  ‘Game Feeds’ and the right-hand Activity bar in  For instance, if you collect 15 on your Games Feed, and 15 on, you would hit the limit, and it won’t be for another 12 hours that you can collect any more items. The 12-hour window is ‘sliding’, meaning that it isn’t set to a specific hour, like noon or midnight.  The timer begins when you begin accepting things from feeds.
All these tips don't apply with gifts from the Inbox.  There seems to be no limit to what can be stored in the Inbox.
With that in mind, if you’d like to really maximize your collection possibilities for what you need, you should use these tips:

  • Check your feeds every 13 hours, and you’ll get 30 more collections.
  • Bookmark your Facebook Games Feed in your browser. That will save a step so you don’t have to find it in the left-hand column of Facebook.
  • Be choosy. If you are low on collections (nearing 30), you should just seek out the things that you need.
  • Be Social. If you actually need something specific, write messages to your friends asking for it.
  • Don’t go to your feeds until after you’ve spent some water and fertilizer, and feed. You forfeit any collected water, feed and fertilizer if you are at your max allowance of those three consumables. The game won’t tell you that, though, so you are just wasting clicks.

We hope these tips are helpful in making sure you are able to get the items that you need.