I want to bring it up at the thing, but I understand many of them were annual meetings and that sounds like a long wait.
Were things held annualy or more frequently? Would an ad hoc thing be held to settle an important case? Were there local things for a villages/towns, or was this something reserved for larger regions?
No, the big political meetings like the Thing of all Swedes (Svear) and were usually held in combination with markets and/or religious festivals.
Common criminal justice was handled by the thing of the lowest administrative level, the hundred (hærað, härad, herred, hérað). How often that occurred depended on the hundred, but for instance the Swedish country law (landslag) of Magnus Erikssons standardized it at once a week .
"Viking" isn't really an identity/ethnicity though. Things weren't the same everywhere.