Today's multistage hydraulic fracturing operations often demand complex treatments that incorporate high injection rates along with high volumes of proppant and fluid. It is challenging, however, to execute these treatments in a time- and cost-efficient manner while still maintaining optimal treatment quality. This paper discusses the applicability and limitations of the simultaneous-fracturing (simul-frac) completion technique - a solution that offers considerable advantages to help operators meet increasing industry demands to "do more with less". Simul-frac involves hydraulically fracturing two or more adjacent horizontal wells simultaneously. This technique provides an effective solution to the challenges mentioned above. A controlled field study was conducted on three four-well pads, on the same Permian Basin lease, with identical/matching well geometry, landing zones, lateral lengths, and treatment designs. Two pads were completed using a traditional zipper-frac operation, while one pad was completed using the simul-frac technique. Designed to analyze operational efficiency, overall completion cost and impact on well productivity, this study provides an unprecedented, precise comparison between simul-frac and traditional zipper completions. The controlled field study provided valuable insight into how the simul-frac technique can affect operational efficiencies. Unlike zipper-frac operations, all four wells on the pad were being either fractured or perforated at the same time, so there was never a time when one or more wells sat idle. By fracturing two stages simultaneously, the crew was able to complete more lateral footage, compared to fracturing a single stage with zipper frac. This, in turn, shortened overall operational time to complete the pad by five days. These saved days reduced overall completion costs and allowed for earlier return on investment by putting the wells on production sooner. Like traditional zipper-frac operations, simul-frac operations are performed by a single frac crew, requiring minimal equipment modification or alteration to treatment execution procedures. However, the simul-frac technique is a complex operation that presents unique risks and challenges, including: simultaneous injection of fracturing fluid into two wells at a higher total injection rate, higher proppant and daily chemical-consumption rate, two cranes and two wireline trucks on the same pad, and pairing of wells with different landing zones. These risks are manageable, and service providers can achieve the desired results by providing exceptional communication and expertise at the wellsite. Simul-frac operations enable operators to execute multistage well stimulation faster and more efficiently. It introduces greater operational efficiencies by enabling the crew to operate at peak performance and by eliminating well idle time. These advantages translate to lower overall completion costs and reduced time to first production.