This study is for anyone 18 years or older who provides unpaid care for a loved one living with cancer outside of the hospital setting. The purpose of this study is to help future caregivers and patients by learning how mental fatigue affects caregivers of persons living with cancer and determine if mental fatigue, participating in self-care activities, and general caregiver quality of life are related. Informal caregivers will be invited to complete a confidential, online survey that takes between 25 and 35 minutes to finish. Caregivers who complete the survey may be contacted and asked to participate in a 45-60 minute follow up interview either online or via phone if they are interested. The results of this study will help guide future research to identify ways healthcare professionals can help caregivers handle the stresses of caregiving and provide the best care possible to their loved ones at home.