Yup, I use mirrors almost every ride. My neck has been injured a few times, pretty badly twice from being hit by cars, so I need mirrors to offset limited range of motion. It's gotten better with physical therapy but I'm still more comfortable with mirrors. And road/wind noise can obscure the approach of some cars, especially newer electric, hybrid and fuel efficient cars that are much more aero and use tires with minimal tread that make very little road noise.
On my hybrids with flat and riser bars, I've used Mirrycle mirrors -- inexpensive and really tough. Mine have survived a few crashes and bike drops.
A couple of years ago I tried Take-A-Look mirrors for my safety glasses and helmets. I have a couple, one mounted to my primary helmet using zip ties, and another that I swap between my clear and tinted safety glasses.
After noticing some 50+ friends using aerodynamic bar-end mirrors (pricey Italian things) on their drop bar bikes, I tried the less expensive Sprintech, which may be even better despite being cheaper. The Sprintech are easy to mount, easy to adjust on the fly but retain the desired position until I knock 'em with my knee or hand. Road vibration won't jar the Sprintech mirrors out of position. Highly recommended for drop bar bikes. The pricier Italian mirrors need to be set in one position and held in place with bar wrap, so it's not easily adjustable while riding. The Sprintech uses a soft rubber plug for the bar-end, with a socket joint for the hard plastic ball-end on the mirror itself. Very handy design, although it's a bit longer than the Italian mirror.
Occasionally when I'm chasing a Strava PR I'll omit the Take-A-Look mirror on my helmet or sunglasses, wear an aero helmet with magnetic mount visor (no place to mount a mirror), and rely on the Sprintech bar-end mirror. I'm still more comfortable with the 1:1 view of the Take-A-Look mirrors -- easier to see approaching vehicles and closing speed at a glance. But the Sprintech helps when I'm approaching tricky intersections with traffic merging diagonally from behind me. My aero helmet and kit are good for maybe a 1 mph improvement over distance, and the Sprintech mirror doesn't seem to add any drag.
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Sprintech bar-end mirrors for drop bars cost about $25 or less for a pair. They're intended to be mounted on both bar-ends of a single drop bar, and are slightly curved rather than neutral in shape. But I've mounted one from the pair on two road bikes, left hand side, and the slightly mismatched curve hasn't been a problem when mounting the "right hand" mirror on the left side.
I particularly like that I can quickly adjust the angle of the Sprintech to suit whichever riding position I'm in. If I plan to work on getting out of the saddle and standing to pedal a lot, I can quickly adjust the mirror so I can glance down occasionally and see behind me. And when I sit to use the drops it takes only a moment to adjust it again. The roughly elongated teardrop shaped mirror is visible from the usual drop bar positions -- tops, hoods, drops -- without any adjustment.