My first robe was a thin polyester thing with a cheap elastic belt that I bought from a supermarket for about eight quid, and it taught me that a robe which doesn't have pockets is basically just a cape. Lovely colour, completely useless, gone within a year because the hem had frayed into something resembling string.
What separates a good one from a sad one usually comes down to weight and how it's finished at the edges. A proper robe has enough fabric in it to actually hang, whether that's a cotton waffle with some texture to it or a velour that feels soft rather than static and clingy. Cheap ones are see through under any decent light, the belt loops come away after a few washes, and the tie itself is often just a strip of the same fabric that goes limp and refuses to hold a knot. On a good one the tie has a bit of structure, the pockets are deep enough to actually hold your phone without it sliding straight out, and the seams at the shoulder don't pucker after a wash. Check the cuffs too. A robe that rides up to your elbow every time you reach for the kettle is not doing its job, however nice the pattern on it.
Mine gets the most wear in the bits of the day that aren't really dressed for anything, mornings with coffee, evenings after a shower, the ten minutes before you've committed to real clothes. A heavier waffle or toweling one earns its stripes after a bath or swim, somewhere between towel and dressing gown. Come winter I want something longer and thicker, nearly to the ankle, something I can wear over pyjamas while the heating catches up. In summer a lighter cotton one that doesn't make you sweat just answering the door to a parcel is worth more than people expect. For travel, a thin packable one that doesn't take up half the case is its own small luxury, hotel robes being hit and miss at best.
On colour, I've learned to avoid anything too pale unless you fancy doing a hot wash every other week, since robes pick up tea stains and toothpaste like nothing else. A mid tone, a soft grey, a deep green, a plain navy, all hide the daily mess far better than white or baby pink ever did. Stripes are forgiving too, and a decent charcoal looks almost smart enough to answer the door in, which a dressing gown has no business doing but mine somehow manages.
Would I actually wear this every single morning, or is it just going to live on the back of a door looking nice and doing nothing?