Background: Sustainability is an important issue in implementation processes in health care, and more knowledge is needed to facilitate improvement work in occupational therapy practice.

Aim: The aim of this study was to explore how occupational therapists experienced continuous quality improvement work based on the Occupational Therapy Intervention Process Model after 17 years.

Method: Two focus group interviews were conducted with a total of 12 occupational therapists. The data were analysed using qualitative content analysis.

Results: The analysis resulted in three themes with related subthemes describing the occupational therapists’ experiences of their model-based long-term improvement work. The themes were labelled as follows: ‘sharing a safe and well-known professional reasoning’, ‘reaching normality and empowerment’ and ‘questioning and reshaping the too safe and too well-known normality’. The model functioned as a sustainable framework both for ordinary clinical practice and for continuous improvement work.

Conclusion: By using the model, the occupational therapists had established a safe and well-known professional reasoning in which continual quality improvement work had become sustainable.