Anywhere: you just do a pause whenever you need it.
Except for an injury: in this case you should write to the support in order to pause your subscription as long as you are injured.
Keep in mind that taking a pause will cause the “week in a row” count (don’t know the English description as I use the App with German settings) to be reset to zero.
Why no training in vacation? (I even trained during my honeymoon 
)