Two pairs of jeans in the same size can behave completely differently. Rigid denim, rise, hip shape and elastane content often matter more than the style name.
Waist and hips are not enough
Also measure rise and inseam. A rise that is too short can pull at the front and back; one that is too long may fold. The same high-rise design reaches different points on people of different heights.
Rigid or stretch denim
One hundred percent cotton denim holds a more structured shape and requires more precision. A small amount of elastane adds tolerance, while very stretchy fabric may loosen during the day.
Read the cut as a whole
Straight, wide, bootcut, flare and skinny mostly describe the leg. They do not automatically tell you how much space exists at the stomach, seat or thigh.
When available, compare thigh measurements with jeans you already like.
Functional fitting
When the jeans arrive, sit, walk, climb a step and wear them for several minutes without removing tags. Jeans that work only while standing are not a good purchase.
On each brand listing, check whether the highest sizes are available in denim, not only elsewhere in the catalogue.