Yeah, I think the 2015 MBP is definitely worth the refresh. It's such a great laptop. I have mine configured to boot natively into 3 different OS's - MacOS, Windows 10, and Fedora Linux. There are community patches, like Open Core Patcher, that will allow you to run the latest OS's with the latest security updates. It was the last great keyboard, there's no annoying Touch Bar, it has all the right ports (except USB-C). It's also the last MacBook that has a user upgradable SSD (but you'll need your original or an OEM from the same exact model to upgrade the firmware for OS's beyond Big Sur. After that, you can put any SSD in and upgrade to Monterey). It's really hard to justify spending so much on the newer MacBooks with all the upgrade abilities. As far as vacuuming your computer, I've done it with no harm, but you really shouldn't. The worry is static electricity frying something on your motherboard. A small amount can do a lot of damage, and it's particularly hard to troubleshoot. They make special vacuums for this task, but if you're not repairing computers for pay, or rich beyond logic, it's likely not worth the investment. Compressed air is a better bet.
