Blood pressure, grip strength and lung function are frequently assessed in longitudinal population studies, but the measurement devices used differ between studies and within studies over time. Despite efforts to promote standardisation of measurement devices, various studies have opted for different devices due to practical considerations. Additionally, in long-term longitudinal studies, the devices used often need to be replaced with more technologically advanced ones that offer improved or extended measurement capabilities, cost-effectiveness, portability, or ease of use as outdated models become obsolete. This poses significant challenges for research that aims to compare findings across studies or track functional changes over time. A randomised, repeated measurements cross-over trial was conducted to compare measurements ascertained from different commonly used devices. Participants were recruited from London and the South East – N=118 men and women (age 45-74 years), whose blood pressure, grip strength and lung function were assessed by two sphygmomanometers (Omron 705-CP and Omron HEM-907), four handheld dynamometers (Jamar Hydraulic, Jamar Plus+ Digital, Nottingham Electronic and Smedley) and two spirometers (Micro Plus by Micro Medical and Easy on-PC by NDD), respectively, in a randomly allocated order. We identified that there are differences in measurement of blood pressure, grip strength and lung when assessed using different devices. For blood pressure, the new Omron HEM-907 measured higher than the older Omron 705-CP. For grip strength, the electronic dynamometers (Jamar Plus+ Digital and Nottingham Electronic) recorded higher measurements than either the hydraulic (Jamar Hydraulic) or spring gauge (Smedley) dynamometer. For lung function, the ndd Easy on-PC measures of FVC were higher than for the Micromedical, but there was no significant difference between measures of FEV1.