With POP3 you can download your hotmail messages and delete them from the online server, freeing up space while you still have your copies on your personal computer.
If you need help with setting up Thunderbird to use as your program for getting email from Hotmail, Gmail or any other service, go to this page here.
Settings for Hotmail POP3:
POP server: pop3.live.com (Port 995)
POP SSL Yes
User name: yourname@hotmail.com
Password: Your password you have been using to access Hotmail or Windows Live
SMTP server: Your internet provider SMTP settings (for example, with comcast you would use smtp.comcast.net) Some people use: smtp.live.com (Port 25 or 587)
Authentication required? Yes
TLS/SSL required? Yes (i have mine set to TLS 1.0 Cyrus)
If you have additional questions, please use the contact form. Thanks.