If you work on multiple Django or Flask projects you&#x27;ll quickly learn APT can start solving your problems but it won&#x27;t be the best way to do it.<p>With virtualenv each project of mine has a requirements file (I use it even for Google App Engine development, having a distinct SDK per project) and runs Python from a different environment where the packages I install with pip do not interfere with any other environment. Without it an &quot;apt-get upgrade&quot; can end up breaking everything (to say nothing about not having the latest version packaged).