If the same logic is needed for both instances, then:

* in an `if` structure they should be combined

[source,ruby,diff-id=1,diff-type=compliant]
----
if (a >= 0 && a < 10) || (a >= 20 && a < 50)
  doFirstThing()
  doTheThing()
elsif a >= 10 && a < 20
  doTheOtherThing()
else
  doTheRest()
end
----

* for a `case`, the values should be put in the `when` expression list.

[source,ruby,diff-id=2,diff-type=compliant]
----
case i
  when 1, 3
    doFirstThing()
    doSomething()
  when 2
    doSomethingDifferent()
  else
    doTheRest()
end
----