OBJECTIVES: This study investigates how prior home blood pressure monitoring (HBPM) experience affects blood pressure variability and evaluates if reduced HBPM regimens could be recommended for experienced patients. METHODS: This posthoc analysis of the TASMINH4 trial included self-monitored blood pressure (BP) data from 225 patients. The standard deviation of systolic BP recordings was calculated for each patient-week to assess how BP variability changes with HBPM duration. A subgroup of 84 patients, who submitted at least 1 reading a day for 7 days at months 1, 3, and 6, was analysed to assess the impact of reduced HBPM regimens on BP estimates. RESULTS: Day 1 readings were significantly higher than day 2-7 in the first 3 months of HBPM: 1.1 (95% CI 0.4, 1.8) day 1 vs. day 2. This effect diminished after 6 months: 1.0 (95% CI -0.8, 2.8) day 1 vs. 2. Long term monitoring significantly reduced intra-week BP variability, with the standard deviation of systolic BP recordings within each patient-week significantly reduced after 6 months. After 6 months of HBPM, the inclusion of day 1 readings or use of an abbreviated monitoring regimen had a reduced impact on estimates of mean systolic and diastolic blood pressure. CONCLUSIONS: Long-term HBPM reduces intra-week BP variability, making day 1 readings insignificantly raised after 6 months of HBPM. This provides rationale for different HBPM recommendations: longer regimes, excluding day one readings, for diagnosis and short-term monitoring; and abbreviated regimes including day 1 for longer term monitoring in those with HBPM experience.