Objectives The literature commonly evaluates those daily activities which are impaired in dementia. However, in the mild stages, people with dementia (PwD) are still able to initiate and perform many of those tasks. With a lack of research exploring variations between different dementia diagnoses, this study sought to investigate those daily activities with modest impairments in the mild stages and how these compare between Alzheimer's disease (AD), vascular dementia (VaD) and mixed dementia. Methods Staff from memory assessment services from nine National Health Service trusts across England identified and approached informal carers of people with mild dementia. Carers completed the newly revised Interview for Deteriorations in Daily Living Activities in Dementia 2 assessing the PwD's initiative and performance of instrumental activities of daily living (IADLs). Data were analysed using analysis of variance and Chi‐square tests to compare the maintenance of IADL functioning across AD, VaD, and mixed dementia. Results A total of 160 carers returned the Interview for Deteriorations in Daily Living Activities in Dementia 2, of which 109, 21, and 30 cared for someone with AD, VaD, and mixed dementia, respectively. There were significant variations across subtypes, with AD showing better preserved initiative and performance than VaD for several IADLs. Overall, PwD showed greater preservation of performance than initiative, with tasks such as preparing a hot drink and dressing being best maintained. Conclusion Findings can help classify dementia better into subtypes in order to receive bespoke support. It suggests that interventions should primarily address initiative to improve overall functioning.