For me, this is one of those "How did I ever live without it?" devices.
This brass shut-off coupling cost between $5 and $10 at my local big box store. Attaching it to my hose makes it very easy for me to quickly switch between using the nozzle to water in my pre-emergent in a new bed, and using the soaker hose to deep water the existing bed next to it. No more treks back to the faucet to turn the water on/off, or kinking the hose to block the water flow while changing hose attachments. Just flip the switch to off, change the attachment, and start the water flowing again.