Background and study aims Expired medical devices represent an environmental and economic concern, yet their magnitude and true shelf life remain poorly defined. We aimed to quantify the volume and cost of expired endoscopic devices and evaluate their sterility and functionality beyond the labelled expiry date. Methods We conducted an investigator-initiated, prospective study (December 2023-May 2025) across 25 endoscopy units from Europe, Canada, and the USA. Expired devices were inventoried during one-week audits. An institutional questionnaire assessed storage practices. Microbiological sterility and ex vivo functionality were assessed in randomly selected samples. Physicomechanical testing included matched case-control comparison with non-expired counterparts. Results We identified 1,448 expired devices (median per centre, 42; range 3-262), with an estimated cost of €192,141.67. Of these, 273 underwent microbiological testing, 210 ex vivo functional assessment, and 57 physicomechanical evaluation. No microorganism growth was detected in any evaluated device (100%, 95% CI 98.6-100). All but one overtube retained functionality (99.5%; 95% CI 97.4-99.9). Physicomechanical testing showed no clinically relevant differences compared with non-expired devices. Only six centres (24%) reported written protocols to minimise accumulation of expired accessories, and three (12%) had electronic tracking systems. Conclusions Expired endoscopic consumables are frequent and costly, with suboptimal inventory management within endoscopy units. In this multicentre bench and ex vivo study, analysed devices preserved sterility and functional performance beyond their labelled expiry dates. These findings challenge current shelf-life assumptions and support further regulatory evaluation, but should not be interpreted as evidence supporting routine clinical use of expired devices.