Objective
Informal caregivers are expected to be willing to care for relatives with care needs. Little is known about whether and how willingness to care changes over time. Using a weekly diary study, we examined changes in the willingness of 955 caregivers from nine countries. Caregivers provided information on their caregiving context, relationship type, and relationship satisfaction with the care recipient.

Methods and measures
For 24 consecutive weeks, caregivers evaluated willingness to care as it was ‘right now’.

Results
Willingness differs from one caregiver to another (68% between-level variability) but also fluctuates in the same caregiver from week to week (32% within-level variability), with a decrease over 6 months (intercept = 8.55; slope = −0.93; p < .001). Regardless of individual differences in average willingness to care based on caregiving context and relationship satisfaction, caregivers reported decreases in willingness. Caregivers who presented one or more health conditions themselves reported higher weekly fluctuations in willingness than caregivers with no health conditions.

Conclusion
Willingness is not a stable attitude because it decreases and caregivers experience fluctuations from week to week. A clearer understanding of weekly processes is optimal for monitoring the caregivers’ well-being and tailoring interventions in line with weekly individual variations.