Control participants will receive SMS reminders of each assessment point and monthly two-way SMS messages to provide AH pill-taking tips and to ask if participants are feeling dizziness or other symptoms of low blood pressure. Participants in the control group will not receive additional adherence reminders, financial incentives, or the Wellth app during the 24-month study.

Participants in the Wellth only group will receive daily financial incentives during the 4-month intervention for providing photo evidence of their pill taking using the mobile app Wellth (i.e. taking a daily picture of their pills in their hand and submitting it through the Wellth app). The Wellth app will also provide reminders at the end of the day if participants have not yet completed their daily check-in. Participants will also receive SMS reminders of each assessment point and monthly two-way SMS messages to provide AH pill-taking tips and to ask if participants are feeling dizziness or other symptoms of low blood pressure.

Participants in the Wellth+Cue group will receive daily financial incentives during the 4-month intervention for providing photo evidence of their pill taking using the mobile app Wellth (i.e. taking a daily picture of their pills in their hand and submitting it through the Wellth app), conditional on using their action plan. The Wellth app will also provide reminders at the end of the day if participants have not yet completed their daily check-in. Participants will also receive SMS reminders of each assessment point and monthly two-way SMS messages to provide AH pill-taking tips and to ask if participants are feeling dizziness or other symptoms of low blood pressure.

Participants will be eligible to receive $30 at the end of four consecutive 30-day periods ($120 in total) if they demonstrate complete medication adherence through the Wellth app (i.e. taking a daily picture of their pills in their hand and submitting it through the Wellth app). Photos must be submitted within a 2-hour window around a specific time of day chosen by the participant and set at the start of each 30-day period. They will lose $2 (from their $30 total) for every day they miss a medication check-in within their pre-set 2-hour window with the Wellth app. The Wellth app will also provide reminders at the end of the day if participants have not yet completed their daily check-in.

The investigators will use Medicaid's prescription data to construct the Primary Outcome of AH medication adherence using the date and supply of pills for each new prescription or refill to determine the number of days in a month a client had pills available. Since refills are often made before an existing prescription ends, the supply of new medications will be counted on days following the last available dose of the prior prescription. The number of days with available AH medication(s) will be divided by the total number of days in the same month to calculate the proportion of days covered (PDC), which will range from 0 and 1.

All participants will be asked to submit blood pressure readings for seven consecutive days after baseline activities, and be reminded via SMS and email to submit readings after the 4-month intervention and again after the month 8, 12, and 24 assessments. The investigators will calculate the Primary Outcome measure of blood pressure as participants' mean and coefficient of variation in systolic and diastolic blood pressure over the seven-day interval.

The investigators will use Medicaid's encounters and reimbursement costs data to construct our Secondary Outcomes of healthcare utilization and costs. The investigators will generate separate monthly measures of the number of unique encounters, as well as the number of days in an emergency department, and inpatient and outpatient healthcare settings. Since a single encounter can be billed multiple times (thus appearing multiple times in the data) or last multiple days, the investigators will remove duplicate encounter claims based on the date of service, diagnostic codes, and procedure costs associated with each encounter. The investigators will separately measure the monthly AHCCCS reimbursement costs for all unique encounters in each healthcare setting.

Habit strength (i.e., behavioral automaticity) will be measured using the Self-Reported Behavioral Automaticity Index (SRBAI), a frequently used 4-item subscale of the Self-Reported Habit Index (SRHI). The SRBAI assesses the degree to which a given behavior (e.g., pill taking) is an automatic or unconscious process. Scores range from 5-20, with higher scores indicating greater self-reported habit strength