  The variability of blazars in the X-ray and optical regions informs both the
physics of their emitting region and places demands on the observer if a
program requires that the object be bright or faint. The extensive simultaneous
X-ray and optical observation by Swift provides the best insight into the
variable nature of these objects. This program uses \textit{Swift} data for 19
X-ray-bright blazars, generally at $z > 0.1$, to determine their variability
properties. The analysis is based on structure functions and provides insight
into the nature of the variability and how it depends on time, luminosity, and
redshift. We also consider strategies for observing blazars at or above average
brightness, given a time delay between planning an observation and obtaining
the data. This is critical to observations with orbiting X-ray telescopes,
current or future. The variability in the soft X-ray band is typically three to
eight times larger than at UV-optical wavelengths, at fixed time differences
(i.e., 30 or 100 days). There is almost no difference in the amplitude of
variation (X-ray or UV-optical) as a function of redshift (time delay of 30
days) and a modest positive correlation with luminosity. In the X-ray band,
blazars that become brighter than normal typically remain bright for at least
2-3 months, although with significant flickering. One can avoid observing
objects that are significantly below the average X-ray flux by scheduling the
observation when the $F_X > 0.9 F_{X,avg}$, which requires monitoring
observations near the time of the scheduling activity.
