Discovery regarding expert witnesses is governed by Pennsylvania’s Rules of Civil Procedure, Rule 4003.5. PA. STAT. AND CONS. STAT. ANN. § 4003.5 (West 2017). This rule explains that discovery regarding expert “fees and expenses” will be left to the court to deem appropriate or not. Id. Case law has held that a discovery request for an expert’s tax returns was too broad of a discovery request. J.S. v. Whetzel, 860 A.2d 1112 (Pa. Super. Ct. 2004). Additionally, the Supreme Court of Pennsylvania has held that a request for financial information as a method to show an expert’s bias was “unduly burdensome.” Cooper v. Schoffstall, 905 A.2d 482 (Pa. 2006). Inquiring into the financial information of experts to impeach them is allowed, but it must not result in changing the focus of the litigation to the expert’s financials. Whetzel, 860 A.2d at 1115.