of the 3 SDM3045 I bought, two were defective, but the good one serves as my secondary bench meter and is a fantastic value. one of them started locking up with increasing frequency, and the other one exhibited this behaviour within a day or two of hitting the bench. I was hoping to hear back from the siglent engineers (you can talk to them on the phone, which is greatly appreciated!), but no word back yet. my suspicion is something up with the SOC on those units, maybe poorly placed heatsinking or something, not sure, but it left a bit of a bad taste in my mouth.
the good unit hasn't locked up once, hasn't had a single hiccup, and is used 7 days a week. the other two units locked up constantly, and all three were on the same firmware if memory serves. what I am saying is that I'd suggest leaving your unit powered up 24/7 for the first few weeks, and if it locks up even once, return it. a working unit is fantastic value, but the lock ups increase in frequency over time, and I would be willing to bet that any units that exhibit lockups at all will just get progressively worse, leaving you high and dry after the warranty period unless a warranty extension program for affected units is put in place.
this is just my experience though, so it's possible I was incredibly unlucky twice. if it were just one meter, I'd have remained on the siglent train, but I got off at the keithly station and haven't looked back since