It's unusual for a feed to be larger than 512KB. However, some publishing tools generate their feeds with no limit on the number of items included in the feed. Such feeds are susceptible to steady size increases.
Go Premium - Increase Your Feed File Size Limits
Users on our Pro plan have had their limit raised to 1024KB (double the Free limit).
If you are currently using dlvr.it and your source feed exceeds the 512K limit, dlvr.it will not post new feed items from the feed until your feed's size drops below the limit. If your feed size exceeds the limit for more than 24 consecutive hours, we'll stop retrieving your feed. You'll need to reduce your feed file size, then log into dlvr.it and reactivate your feed.
For most feeds this will never be an issue. However, but if your content postings are regularly very large in size, you might want to monitor your feed's size. If you use Blogger, you may follow these steps to reduce your feed file size below 512K if it currently too big.
If you are set up to receive status alerts from dlvr.it, we'll alert you if your feed exceeds the limit and your feed retrievals are deactivated.
To check the current size of your feed
You can check the size of your feed by using a service such as web-sniffer.net - enter the URL for your feed, uncheck "Accept-Encoding: gzip", select the "HEAD" method, and hit Submit. Your feed's size should be listed in the Content-Length field.
This method does not always work for all services, and sometimes can present a Content-Length that is incorrect, but it is the fastest tool available.