710: That New Mouse Pad Feeling

What It Covers

John Siracusa migrates from a 2019 Mac Pro to an M5 Max Mac Studio after seven years, while all three hosts detail their iPhone 18 Pro, AirPods 5, Apple Watch Series 12, and Mac mini M6 purchases. The episode also covers iPhone Duo developer tool delays, St. Jude fundraising, and Apple Watch readiness score validity concerns from cardiologists.

Key Questions Answered

• •iPhone Battery Management: Setting an 80% charge limit on an iPhone 16 Pro over nearly two years resulted in 95% battery health at 451 cycles. When the limit was removed in the final months before upgrade, the phone felt like it had a new battery. This strategy works particularly well for devices that stay stationary, like iPads permanently at a bedside, where a permanent 80% cap makes practical sense without sacrificing daily usability.
• •iPhone-to-iPhone Transfer Resilience: Apple's phone-to-phone transfer process fails silently and catastrophically — any accidental input on the source device, including pressing the camera control button while plugging in a cable, immediately terminates the transfer and forces a full erase of the destination phone with no confirmation prompt. The practical workaround is to wait until all file sizes finish calculating on the selection screen before proceeding, then leave both phones completely untouched on chargers.
• •Migration Assistant Patience Threshold: When transferring four terabytes across Macs via Thunderbolt 5, Migration Assistant displays an indeterminate back-and-forth progress bar labeled "starting up" for approximately 50 minutes before switching to a real progress bar with data rates and time estimates. Users who abandon the process during this phase miss the actual transfer beginning. Sustained transfer speeds reached over one gigabyte per second, completing the full four-terabyte migration in roughly four hours.
• •Apple Watch Ceramic Coating Durability: The gold DLC coating on Apple Watch Series 10 visibly tarnishes over 18 months, with color differences appearing between skin-contact areas and the rest of the case. Fine jewelry polishing cloths can partially restore appearance but work through abrasion that removes thin DLC coating layers, risking permanent damage. The white ceramic Series 12 avoids this issue entirely since ceramic has no coating to degrade, making it a more durable long-term material choice.
• •Apple Watch Series 12 Bezel Trade-off: The Series 12 has measurably thicker bezels than the Series 10 and 11, which Apple previously marketed as a key achievement. However, the thinner bezels on Series 10 pushed screen content onto the curved crystal edges, distorting readability. The Series 12 pulls content back onto the flat face, improving legibility. Users with black watch faces will not notice the bezel difference at all, making this a functional improvement despite the spec regression.
• •iPhone Duo Developer Timeline Problem: Apple's internal secrecy compartmentalization means the team building Duo simulator tools is walled off from the main Xcode team, causing version sequencing anomalies where Xcode 27.2 beta shipped before 27.1. The structural fix is not faster SDK delivery on announcement day — it is extending the consumer availability window by at least two months for hardware requiring significant layout changes, giving developers adequate time to update touch targets, screen size handling, and multi-screen interaction patterns before one-star reviews accumulate.
• •Wearable Readiness Scores Are Unvalidated: Cardiologist-cited research confirms that readiness scores on devices including Apple Watch use proprietary, undisclosed algorithms that have not been validated against actual health outcomes. This applies equally to Whoop, Oura, Garmin, and Suunto products. The scores can be useful as behavioral feedback loops — moving the number correlates with some underlying metric — but should not be treated as clinical data. Apple includes disclaimers, but the marketing framing consistently overstates the medical significance of these composite scores.