I know that if the number of repositories exceeds 10 then we need to prioritize that. But I don't know how.
I've have got 28 repositories added right now.

Code:
akash:~ # zypper lr -d
#  | Alias                         | Name                               | Enabled | Refresh | Priority | Type   | URI                                                                                         | Service
---+-------------------------------+------------------------------------+---------+---------+----------+--------+---------------------------------------------------------------------------------------------+--------
 1 | CrossToolchain:avr            | CrossToolchain:avr                 | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/CrossToolchain:/avr/openSUSE_13.2/                |        
 2 | LibreOffice_4.3-openSUSE_13.2 | openSUSE_13.2-LibreOffice_4.3      | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/LibreOffice:/4.3/openSUSE_13.2/                   |        
 3 | X11:Enlightenment:Factory     | X11:Enlightenment:Factory          | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/X11:/Enlightenment:/Factory/openSUSE_13.2/        |        
 4 | devel:languages:perl          | devel:languages:perl               | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/devel:/languages:/perl/openSUSE_13.2/             |        
 5 | devel:languages:python        | devel:languages:python             | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/devel:/languages:/python/openSUSE_13.2/           |        
 6 | games:tools                   | games:tools                        | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/games:/tools/openSUSE_13.2/                       |        
 7 | home:Nemton                   | home:Nemton                        | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/home:/Nemton/openSUSE_13.2/                       |        
 8 | home:malcolmlewis:TESTING     | home:malcolmlewis:TESTING          | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/home:/malcolmlewis:/TESTING/openSUSE_13.2_Update/ |        
 9 | home:mreggie                  | home:mreggie                       | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/home:/mreggie/openSUSE_13.2/                      |        
10 | home:srinidhi                 | home:srinidhi                      | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/home:/srinidhi/openSUSE_13.2/                     |        
11 | openSUSE-13.2-0               | openSUSE-13.2-0                    | No      | No      |   99     | yast2  | hd:///?device=/dev/disk/by-id/scsi-1PHISON_USB3-part2                                       |        
12 | openSUSE:13.2                 | openSUSE:13.2                      | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/openSUSE:/13.2/standard/                          |        
13 | openSUSE_13.2-Bumblebee       | openSUSE_13.2-Bumblebee            | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/X11:/Bumblebee/openSUSE_13.2/                     |        
14 | openSUSE_13.2-Education       | openSUSE_13.2-Education            | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/Education/openSUSE_13.2/                          |        
15 | openSUSE_13.2-electronics     | openSUSE_13.2-electronics          | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/electronics/openSUSE_13.2/                        |        
16 | openSUSE_13.2-games           | openSUSE_13.2-games                | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/games/openSUSE_13.2/                              |        
17 | openSUSE_13.2-libdvdcss       | openSUSE_13.2-libdvdcss            | Yes     | Yes     |   99     | rpm-md | http://opensuse-guide.org/repo/13.2/                                                        |        
18 | openSUSE_13.2-packman         | openSUSE_13.2-packman              | Yes     | Yes     |   99     | rpm-md | http://packman.inode.at/suse/openSUSE_13.2/                                                 |        
19 | openSUSE_13.2-science         | openSUSE_13.2-science              | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/science/openSUSE_13.2/                            |        
20 | openSUSE_13.2-wallpapers      | openSUSE_13.2-wallpapers           | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/repositories/artwork:/wallpapers/openSUSE_13.2/                |        
21 | repo-debug                    | openSUSE-13.2-Debug                | No      | Yes     |   99     | NONE   | http://download.opensuse.org/debug/distribution/13.2/repo/oss/                              |        
22 | repo-debug-update             | openSUSE-13.2-Update-Debug         | No      | Yes     |   99     | NONE   | http://download.opensuse.org/debug/update/13.2/                                             |        
23 | repo-debug-update-non-oss     | openSUSE-13.2-Update-Debug-Non-Oss | No      | Yes     |   99     | NONE   | http://download.opensuse.org/debug/update/13.2-non-oss/                                     |        
24 | repo-non-oss                  | openSUSE-13.2-Non-Oss              | Yes     | Yes     |   99     | yast2  | http://download.opensuse.org/distribution/13.2/repo/non-oss/                                |        
25 | repo-oss                      | openSUSE-13.2-Oss                  | Yes     | Yes     |   99     | yast2  | http://download.opensuse.org/distribution/13.2/repo/oss/                                    |        
26 | repo-source                   | openSUSE-13.2-Source               | No      | Yes     |   99     | NONE   | http://download.opensuse.org/source/distribution/13.2/repo/oss/                             |        
27 | repo-update                   | openSUSE-13.2-Update               | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/update/13.2/                                                   |        
28 | repo-update-non-oss           | openSUSE-13.2-Update-Non-Oss       | Yes     | Yes     |   99     | rpm-md | http://download.opensuse.org/update/13.2-non-oss/
Of 28, 5 are disabled.