What are the factors used to determine whether an expert’s fee is excessive?

The assessment of what is fair and reasonable in any given case is as much about what disbursements are fair and reasonable as it is about what fees are fair and reasonable: Hamfler v. 1682787 Ontario Inc., 2011 ONSC 3331, [2011] O.J. No. 6190 at para. 17, where Edwards J. provided the following non-exhaustive list of factors for the court to consider when determining the reasonableness of whether an expert’s fee is excessive: 1. Did the evidence of the expert make a contribution to the case, and was it relevant to the issues? 2. Was the evidence of marginal value or was it crucial to the ultimate outcome at trial? 3. Was the cost of the expert or experts disproportionate to the economic value of the issue at risk? 4. Was the evidence of the expert duplicated by other experts called by the same party? Was the report of the expert overkill or did it provide the court with the necessary tools to properly conduct its assessment of a material issue?