How can I avoid clearing caches when CSS changes are made?
Install AdvAgg, go to admin/config/development/performance/advagg and set "AdvAgg Cache Settings" to "Development"

If you don't want to do that, go to admin/config/development/performance and uncheck "Aggregate and compress CSS files" as well as "Aggregate JavaScript files"

Another option is to install the admin menu module. That has an option to just clear the css/js cache.