Detector R&D is addressed here in the context of experimental concepts developed for future e-e and h-h colliders. Performance goals and operation conditions that drive the associated detector designs are briefly reminded. The R&D needed and the technology trends to provide appropriate technical solutions are then discussed, based on the state-of-the-art detectors prepared for ongoing experiment upgrades. The outline is by experimental sub-systems used for tracking, calorimetry, particle identification, precise time of flight measurements and muon measurements. Eventually, hints of ancillary component developments are mentioned.