This study determined how long it would take skilled operators to deliver 16 J/cm2 to an anterior or a posterior restoration using different light-curing units (LCUs). Three skilled operators used the following LCUs at two locations in the MARC-patient simulator: Optilux 501 standard mode for 20 s; Sapphire Supreme for 5 s; Elipar™ S10 for 5 s and 20 s; Demi™ Plus standard mode for 5 s; SmartLite® Max boost mode for 5 s and continuous mode for 20 s; Radii Plus for 30 s; Valo (main version) in standard mode for 20 s and Xtra Power mode for 3 s; and Valo Cordless in standard mode for 20 s and Xtra Power mode for 3 s. The three MARC-trained operators made 30 readings with each light over 7 days. The energy (J/cm2) delivered to the anterior Class III and posterior Class I simulated restorations in MARC was recorded using a laboratory-grade spectroradiometer, and the time each light would take to deliver 16 J/cm2 calculated. ANOVA and Fisher’s PLSD tests compared differences in the time to deliver 16 J/cm2 of energy, α = 0.05. Three-way ANOVA showed there was no significant difference between the operators, but there was a difference between the lights and locations. The Valo main and Valo Cordless in the Xtra Power mode delivered 16 J/cm2 in the shortest time at both locations. The Radii Plus took the longest to deliver 16 J/cm2, taking twice as long in the posterior location.