What you can tell from a garment in your hand
Short answer: Pull gently at the edges, hold it up to the light and feel the seams. Those three checks tell you most of what you need about how a piece will hold up.
Pull at the edges
If the rib and waistband spring back, they will hold after washing too. If they stretch out, it only gets worse. See bamboo T-shirts for men.
Hold it up to the light
If you can see clearly through it, the fabric is light. That is not bad, but it tells you something about how it will behave. See bamboo T-shirt for women.
Feel the seams
Run a finger along the inside. Raised seams on the inner thigh or at the side are the ones that can rub. See bamboo underwear for men.
Look at the waistband
The width and whether it is sewn on all the way round decide the lifespan. See bamboo briefs.
Read the label
The elastane content tells you whether the piece springs back into shape. See washing and care.
Frequently asked questions
How do I judge a garment?
Pull at the edges, hold it up to the light and feel the seams on the inside.
What does it mean if the rib does not spring back?
That the elastic is weak from the start, and that it only gets worse after washing.
Is light fabric bad?
No, but it drapes differently and can be see through in pale colours.