Proton Exchange Membrane Fuel Cells (PEMFC) durability of stationary systems should be improved for large scales development and commercialization. The aim of this work is to improve degradation understanding in order to propose operating strategies enhancing lifetime and to design specific accelerated tests experiments for micro-CHP application and reformate operation. This paper is focused on results obtained on performance and membrane electrodes assemblies (MEAs) degradation during ageing tests of PEM fuel cells stacks. Durability tests conducted on short stacks over hundreds of hours (up to 900 h) showed how the fuel composition, particularly carbon monoxide content, and the load cycles profiles are impacting on performance degradation rates. The analyses of each cell by electrochemical diagnostics show the modifications of MEAs properties caused by the degradation occurring in both cathode and anode catalyst layers. Results allowed proposing major accelerating features and subsequent relevant accelerated tests, enhancing particularly the ruthenium dissolution identified as the specific limiting mechanism. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.