Hi cfox314,
Welcome to this Apple (user-to-user) Community!
Re: "MacBook Air Drops WiFi : My and my wife's computers (same model, different ages) drop WiFi
connection sometimes every few minutes, sometimes after several hours. No other WiFi connected device in my home does this (phones, tablets, video streamers, etc.)". ... ... "This has been going on for 6 months."
Am no expert in this area, yet your post to the community deserves some response.
Wondering which MacBook Air model we are trouble-shooting.
If needed: How to: Identify your MacBook Air model - Apple Support
Below are a few suggestions toward finding a solution.
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(1) Keeping MacOS updated to the newest compatible MacOS version often avoids difficulties,
ie: mostly because any recommended bug-fixes and security updates are included in the update.
Eg: Seems you are using MACOS Sequoia 15.6 on the MacBook Air
Apple support's online article: What's new in the updates for macOS Sequoia - Apple Support
says the newest MacOS Sequoia version is macOS Sequoia 15.7.2
"This update provides important security fixes and is recommended for all users."
(Reminder: It is always wise to back up your Mac beforehand, if you choose to update.)
Newest update for MacOS 26 Tahoe is now 26.1
Some of us upgrade early to have access to the new features, while others prefer to wait until any (almost inevitable) software bugs come to light, and have been addressed in the frequent updates.
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(2) Disconnection issues can arise from wireless interference:
Wondering whether Apple Support's online article may help:
See how to: Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support
✽ Restarting the router, and / or restarting the Mac (Apple Menu > Restart) can be helpful at times
✽ For network administrators and others who manage their own network: or for updating router firmware:
You may want to browse: Recommended settings for Wi-Fi routers and access points - Apple Support
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(3) If you use third-party (non-Apple) apps on your Mac:
There may be interference issues with your Apple apps.
✽ Unnecessary apps like ad-blockers, virus checkers, cleaners and the like (even VPN) often cause issues. If installed, you can try turning them off (or use uninstallers from their developers) to see if that helps.
✽ Out-of-date browser extensions can also cause issues ... turn off / uninstall / or update if possible.
✽ Ensure no excessive amounts of blocked contacts have accrued from a third-party app.
✽ Any necessary third-party apps may need updating to remain compatible with your Mac's system
All the best :-)