Extech DMMs have a "power-saving" feature that powers off the meter after 15 minutes. That's 15 minutes after turning it on, not 15 minutes after last measurement. It beeps a minute before shutting down, but if you're in the middle of a circuit with probes in hand, it's not fun to watch the display go blank.
On some of their meters this feature can be disabled, but then you're too often staring at a dead battery.
And for aging eyes, these meters have what looks like an infinitesimal decimal point (compared, for example, to a Fluke DMM display).
And Fluke's meters power off after X minutes of lack of use since *last measurement*, and have a large, clear display.
My advice: stay away from Extech DMMs. I do have an Extech IR thermometer and anemometer which work fine. But for a mainstay tool like the DMM, it's strictly relegated to the back of the tool box now.