It seemed rare for Jonathan Frid to get much time off from the show. Even when he was sent off to Wyndecliff in the fall of '68 following Angelique's shenanigans, Barnabas was only off the canvas for 8 shows (2 weeks). He got a longer vacation from the series during the 1897 storyline (most of September '69), and in an interview he mentioned getting to go to Europe during the series' run - maybe this was when he flew abroad without his bat wings.
John Karlen went over to "Love Is A Many Splendored Thing" on CBS while Willie did his stint at Wyndecliff in '67-'68. Karlen's character was short-lived on the other soap, but Willie was MIA from the Collinwood action from late September 1967 until May 1, 1968, when back he came - to taunt a captive Adam with a chicken leg.
Julia may not have been a by-the-book doctor, but she sure never took any time off for herself, or at least by choice. She could have attributed her bad medical choices to lack of relaxation and rest (and lust).