Pocket doors are one of my fave design features in our home, definitely one I would plan again. There is no wasted space, they just slide away into the cavity, totally out of the way, no banging doors and a really stream lined look.
Our architects used pocket doors to create virtual en suites in the secondary bedrooms. Each bedroom is placed next to a bathroom, and a cleverly designed pocket door closes off the bedroom and bathroom area, effectively creating a private en suite (see plans below). It is a genius idea because the bathroom is lovely and private by night, but can be accessed by all of the family during the day.
See how easy? Totally open to totally private instantly.
In the plans below the pocket door is green and you can see how it separates the entire bedroom and bathroom area from the play room. Especially brilliant now that we have a teenager in the house.
Cost wise they are relatively expensive, especially if you plan them before you build. Retrofitting is always a little more costly.
We also used pocket doors to close the butlers pantry and laundry off from the kitchen.
This is one of my favourite features that our architects included in the design and something I would never have thought of myself. Working with an architect in the design phase is an absolute must to get this level of detail.