Tweets can be archived by keyword in your HootSuite dashboard. An archive can store seven days of retroactive content or 1,500 Tweets, whatever limit is reached first. However, the limit can also vary depending on your HootSuite account:
Pro HootSuite account - 100 Tweets. Optional upgrades: 10,000 Tweets for $10 or 100,000 Tweets for $50.
Enterprise HootSuite account - 100,000 Tweets as a default, but can be increased.
You will receive an email when your Tweet archive has reached its limit. The archived Tweets must be downloaded or deleted before you can create a new archive.