Within the BDSM community, 24/7 relationships have long been considered an "ideal," and are a profound sexual fantasy for many if not most BDSM players. However, some BDSM community members may be deeply skeptical of their practicality.
Like all 24/7 relationships, vanilla or otherwise, the 24/7 D/s relationship requires a great commitment from both parties. Because D/s relationships are considered erotic or are thought to conform to the dynamics of "play," they are often not given the consideration or seriousness that people would give, for example, a vanilla 24/7 relationship like a marriage. In fact, 24/7 D/s relationships are a profound commitment and every bit as much a lifestyle choice as marriage.
That said… 24/7 D/s relationships are very real. This is a viable lifestyle choice for a growing number of people who find that their preferred relationship dynamics are best described in concrete, negotiated and in many cases absolute terms.