Mechanical Keyboards

A hot-swap PCB has small sockets under each key instead of switches soldered permanently in place, so you can pull switches out and replace them with a different type -- linear, tactile, or clicky -- using just your fingers or a simple tool, no soldering iron required. It's valuable if you're not sure which switch feel you'll prefer, or want to experiment or upgrade later without buying a whole new board.

No -- VIA in particular is a graphical app, no code or command line involved, where you click a key on an on-screen keyboard layout and assign it a new function. Most people use it for basic remaps and macros without ever touching QMK's underlying config files directly; the deeper firmware-level customization is there if you want it, but isn't required to get the basic remapping benefit.

Generally yes -- shorter key travel means less distance for the stem to move and a shorter, softer bottom-out, which tends to produce a quieter, more subdued sound than full-height switches of the same type. They're not silent, but it's a real, noticeable difference, which is why several low-profile boards are marketed specifically as office-friendly.

Manufacturer-quoted figures, often 100-plus hours, are usually measured with backlighting off. Running RGB backlighting continuously can cut real-world battery life to a fraction of that, sometimes just a few days of typical office use -- if battery life matters more to you than lighting, keep the backlight off or on a low/auto-off setting.

A 75% layout keeps the function row and arrow keys but drops the separate numpad and compresses some spacing and navigation keys into a denser layout. TKL (tenkeyless, roughly 80%) drops just the numpad and keeps a fuller navigation cluster with more standard spacing. Either is fine for most typing or coding use -- the numpad is the main functional loss, which matters mostly if you do heavy numeric data entry.