HTC T-Mobile G2 User Manual page 139

Gmail
A dialog for that conversation label opens, with three options:
Sync none Don't download any conversations that have only this
label.
Sync 4 days Download the previous 4 (or number of days you set)
of conversations.
Sync all Download all conversations with this label.
To set how many days of conversations to synchronize
1 Open your Inbox.
Press Menu and touch More > Settings > Labels.
2
Touch Number of days to sync.
3
Enter the number of days and touch OK.
4
T-Mobile G2
139
User's Guide