The main problem I encountered is that when setting it up (this is for IMAP), there is no option to avoid downloading all the emails on the server. I have 8 email accounts, and each account has several thousand emails. One of them, a Hotmail account that is over 20 years old, has more than 18,000 emails.
In the Synchronization & Storage settings, I set it to only synchronize the emails from the last 30 days. Thunderbird will download the complete emails from the last 30 days, but it will still download the email headers of all the emails on the server, and there is no way to turn off this feature.
Taking the Outlook desktop as an example, I can set it to only download emails from approximately the last 30 days and not download all the email headers. This really makes the entire email application much lighter. After all, most of the time I only need to receive new emails instead of searching through a large number of outdated ones.
