Nice article,  alternatively...

SET DATEFIRST 1 -- force monday as the beginning of the week

DECLARE @bdy datetime,

 @RetiralAge smallint

SET @bdy='24-jul-1971'

SET @RetiralAge=65

SELECT  datediff (dd,getdate()+(8-datepart(dw,getdate())),dateadd(year,@RetiralAge,@bdy))/7  as "Mondays till you retire"

-Ally