I recommend that everybody keep a USB mouse and USB keyboard handy. Whether you use a Bluetooth keyboard and mouse or ones connected by USB cables, I think you should keep a spare keyboard and mouse and this spare set should have USB cables. I recommend this for a couple of reasons.
The primary reason is that you never know when an accident will happen. A glass of water could easily be spilled and this could cause either a keyboard or mouse to malfunction.
If you typically use a bluetooth keyboard or mouse you could find yourself in a pinch if the batteries die and you don’t have any replacement batteries on hand.
Since it’s impossible to use a computer without a keyboard and mouse, you should have a spare of each device handy. Perhaps you could hold onto an older USB keyboard and USB mouse that came with a previous Mac. Or, you could even use a USB keyboard and USB mouse that came with a PC. If you want to buy some spares Macally offers some basic USB mice starting at about $15. Macally offers USB keyboards starting at $30. They even currently offer both a USB keyboard and mouse for about $30. Logitech also offers some inexpensive peripherals. Logitech offers both a USB keyboard and USB mouse for about $20. Logitech’s M100 mouse has cost about $10 for many years. Their K120 keyboard costs about $20.