Template:Dated maintenance category
From Wseven
{{#ifexpr:{{#if:Template|0|1}}+{{#ifeq:no|yes|0|1}}
|{{#if: |[[Category:{{{1}}} {{{2}}} {{{3}}}]]{{#ifexist:Category:{{{1}}} {{{2}}} {{{3}}} ||}} |[[Category:{{#if: |{{{5}}}|{{{1}}}}}]]}}{{#if: |[[Category:{{{4}}}]]}}|}}