Since I installed openSUSE Leap 42.1 my btrfs root partition has been inching toward its limit of 22 GB with all the updates that have been raining in since then!

Who can tell me what snapper configurations I can ditch and what to keep? Some of them are marked 'important = yes', so I have kept them, but I suspect that these are the ones taking disk space.
What does 'important' mean in this context? The bit of documentation I found wasn't really helpful (e.g. I should get rid of the early ones, but they are all 'important'). Am I right in thinking that cleanup is done 'automatically' (i.e. part of OpenSUSE Leap configuration) at boot or shutdown, so that I don't need to change anything there?

My snapper list:
Code:
Type   | #   | Pre # | Date                         | User | Cleanup | Description           | Userdata     
-------+-----+-------+------------------------------+------+---------+-----------------------+--------------
single | 0   |       |                              | root |         | current               |              
single | 1   |       | Sun 08 Nov 2015 00:41:40 CET | root |         | first root filesystem |              
pre    | 290 |       | Wed 02 Dec 2015 11:38:55 CET | root | number  | zypp(y2base)          | important=yes
post   | 291 | 290   | Wed 02 Dec 2015 11:40:21 CET | root | number  |                       | important=yes
pre    | 320 |       | Wed 09 Dec 2015 10:19:11 CET | root | number  | zypp(y2base)          | important=yes
post   | 321 | 320   | Wed 09 Dec 2015 10:28:00 CET | root | number  |                       | important=yes
pre    | 390 |       | Mon 28 Dec 2015 18:09:36 CET | root | number  | zypp(y2base)          | important=yes
post   | 391 | 390   | Mon 28 Dec 2015 18:11:17 CET | root | number  |                       | important=yes
pre    | 550 |       | Sat 30 Jan 2016 09:23:55 CET | root | number  | zypp(y2base)          | important=yes
post   | 551 | 550   | Sat 30 Jan 2016 09:28:00 CET | root | number  |                       | important=yes
pre    | 627 |       | Thu 18 Feb 2016 07:55:56 CET | root | number  | yast sw_single        |              
pre    | 628 |       | Thu 18 Feb 2016 07:56:42 CET | root | number  | zypp(y2base)          | important=yes
post   | 629 | 628   | Thu 18 Feb 2016 08:02:57 CET | root | number  |                       | important=yes
post   | 630 | 627   | Thu 18 Feb 2016 08:03:09 CET | root | number  |                       |              
pre    | 631 |       | Fri 19 Feb 2016 10:45:34 CET | root | number  | yast sw_single        |              
pre    | 632 |       | Fri 19 Feb 2016 10:46:25 CET | root | number  | zypp(y2base)          | important=no 
post   | 633 | 632   | Fri 19 Feb 2016 10:46:56 CET | root | number  |                       | important=no 
post   | 634 | 631   | Fri 19 Feb 2016 10:47:06 CET | root | number  |                       |              
pre    | 635 |       | Fri 19 Feb 2016 10:48:19 CET | root | number  | yast snapper          |              
post   | 636 | 635   | Fri 19 Feb 2016 10:49:36 CET | root | number  |