Carlson v. Bos
In Carlson v. Bos, 740 P.2d 1269, 1271 (Utah 1987), the Court explained that "the words 'under all the circumstances' embody the idea that a plaintiff must act diligently and take such steps in attempting to give the defendant actual notice of the proceeding as are reasonably practicable." 740 P.2d at 1275.
A determination of reasonable diligence thus properly focuses on the plaintiff's efforts to locate the defendant.
Relevant factors may include the number of potential defendants involved, the projected expense of searching for them, and the number and type of sources of available information regarding their possible whereabouts, see id. at 1276, but do not include assumptions regarding a defendant's interest in the rights to be adjudicated.