In the expanding universe,
velocities (v) tend to be well determined and distances (d) are usually the main problem.
But velocity perturbations are actually frequent and significant. For spirals and ellipticals the largest velocity perturbation in the vicinity is the Great Attractor:
For clusters of galaxies,
(Lauer & Postman 1993). In CDM simulations with 
= 1 (Turner et al
1992),
There are two ways of answering the question posed in the title. One is to understand the local velocity fields; the other is to measure distances sufficiently far from us that the unknown quantities in the velocity field are negligible compared with the recession velocity.