In Proulx v. Wells, 235 S.W.3d 213 (Tex. 2007), the Texas Supreme Court considered whether a nine-month delay between the time the suit was filed and substituted service was effected demonstrated lack of diligence as a matter of law. 235 S.W.3d at 215-16. The following timeline summarizes the service efforts in Proulx: May 2, 2003 -- lawsuit filed May 20, 2003 -- process server received citation May 21, 2003 -- limitations expired May 21, 2003 to July 22, 2003 -- eleven attempts to serve at given address July 31, 2003 -- in-house investigator locates three alternative addresses August 5, 2003 to September 17, 2003 -- twelve attempts to serve October 17, 2003 to December 5, 2003 -- seven attempts to serve by second process server December 5, 2003 to December 10, 2003 -- twenty phone calls made to defendant's brother who resided at defendant's address December 5, 2003 -- private investigator hired to locate defendant who concludes defendant was moving to evade service and suggests substitute service January 15, 2004 -- motion for substituted service filed January 26, 2004 -- service effected by substituted service (Id. at 214-15.) "The court of appeals identified specific periods of delay in Proulx's service efforts, and concluded Proulx was not diligent in effecting service during these times." Id. The court of appeals specifically noted a nineteen-day period from the lawsuit's filing to the first process server's receipt of citation; three weeks that passed between dismissal of the suit for want of prosecution and the filing of a motion to reinstate; a nearly five-month period that passed before Proulx hired a private investigator to locate the defendant; twenty-four days that passed before citation was delivered to the second process server; and the overall nine months that passed between filing of suit and successful service. Id. at 216-17. Nonetheless, the Texas Supreme Court concluded the mere fact "that some periods of time elapsed between service efforts does not conclusively demonstrate that Proulx was not exercising diligence in his efforts to locate" the defendant. Id. at 217. "In light of the evidence that was presented regarding Proulx's continuous investigation and repeated service attempts, coupled with evidence that the defendant was deliberately avoiding service," the court concluded that the defendant "failed to conclusively establish lack of diligence" and held that summary judgment was erroneously granted. Id. "Once a defendant has affirmatively pled the limitations defense and shown that service was effected after limitations expired, the burden shifts to the plaintiff to explain the delay." "Thus, it is the plaintiff's burden to present evidence regarding the efforts that were made to serve the defendant, and to explain every lapse in effort or period of delay." Id. "In assessing diligence, the relevant inquiry is whether the plaintiff acted as an ordinarily prudent person would have acted under the same or similar circumstances and was diligent up until the time the defendant was served." Id. "Generally, the question of the plaintiff's diligence in effecting service is one of fact, and is determined by examining the time it took to secure citation, service, or both, and the type of effort or lack of effort the plaintiff expended in procuring service." Id. However, "the plaintiff's explanation of its service efforts may demonstrate a lack of due diligence as a matter of law, as when one or more lapses between service efforts are unexplained or patently unreasonable." Id. "But if the plaintiff's explanation for the delay raises a material fact issue concerning the diligence of service efforts, the burden shifts back to the defendant to conclusively show why, as a matter of law, the explanation is insufficient." Id.