I went on vacation recently where I'd be spending much of my time at the pool and beach. I'm pretty anal about knowing what the time is, so I got myself an $11 Casio watch at Walmart.

I haven't taken it off since. I use it for everything from taking a shower to giving my son a few minutes to finish playing with whatever he is playing with[1]. On the other hand, pulling your phone from your pocket, reaching for it from the desk/counter, and especially "where the hell is my phone" is far too taxing when all you want to do is tell time.

[1] Before the watch, I'd give him the "Alright, it's time for bed — how about you play for 5 more minutes," and just lose track of time which lead to inconsistency, which usually leads to frustration in children. Giving him 5 minutes and then saying "ok time's up" in 1 minute has to be frustrating. Conversely, giving him 5 minutes and letting him keep playing for 15 minutes results in future "I know you're bluffing," attitude.

Granted, sometimes a simple "once you're done playing with x, then it's time for bed," suffices. No need to go all-out Pavlov.