The double ageing evolution in Europe is a tremendous challenge for health care. Older adults with a personality disorder place an additional burden: they have more somatic and psychiatric co-morbidity than those without a personality disorder. Moreover, they experience less quality of life than individuals without personality disorders. This is in sharp contrast to the dearth of empirical research concerning the construct of personality disorders in later life, the very limited amount of available diagnostic tools, criteria of classification systems like DSM not being attuned to the elderly context and the lack of age-neutrality of popular instruments to measure personality disorders. Therefore, in the Netherlands and Belgium a start was made to develop and validate age-specific instruments and to examine the applicability of the alternative dimensional-hybrid DSM-5 classification of personality disorders in older adults. These recent developments and how to apply them for a personalized assessment in older adults will be discussed. Finally, we advise a phased test-based diagnostic approach in which the above-mentioned instruments, combined with measures of adaptive features or more specific tests, can contribute to an assessment optimizing the balance between restricting the load for the older patient and still being sufficiently comprehensive to result in a personalized approach of the diagnostic process.