I recently spent a day clearing out my late mother’s wardrobe. It has been two years since she died so it was time to move on. There were four wardrobes and two chests of drawers – 10 black bags full of clothes for charity. And seven large boxes of other pieces that I will wear myself, give to family and friends and sell to raise money for Kidney Research.

What struck me as I sorted through the rails was first, what consistent taste my mother had – lots of black, lots of layers – and second, how she never threw anything away. She didn’t buy clothes excessively, rather accumulated them over a lifetime. And every piece she bought, whether it was from St Michael (Marks & Spencer stopped using the brand on its labels in 2000), H&M (back when the labels read Hennes & Mauritz) or Helmut Lang, she treated as equals. A vintage kimono; a coat she made in the 80s from a Kenzo Vogue dressmaking pattern; the smart black jacket ordered from Asos; or the 40-year-old oversized T-shirt from Miss Selfridge were all immaculately kept, carefully hung up or folded, buttons all intact, not a stitch out of place. She did not differentiate between high-street bargains and Sunday best. She cherished all her clothes, whatever the price tag.

So, when Dr Mark Sumner, a lecturer in fashion and sustainability at the University of Leeds, told MPs at the environmental audit committee’s investigation into the sustainability of the fast fashion industry that high-street clothes can be more durable than designer ones, it resonated with me. “There’s no correlation to say that price will give you an indication to say which product will wear out,” he said.

Some fast fashion is cheap, nasty and will fall apart after a few washes. The same can be true of designer clothing. It is a misconception that expensive in any way equates to sustainable, or, as Dr Sumner says, durable (though it’s worth remembering that cheap clothes often mean labour exploitation). As my mother’s wardrobe testifies, if you have a good eye for clothes that are stylish rather than fashionable, choose carefully: look for the best-quality fabrics you can afford, and treat the clothes you buy with the utmost respect, care and love (yes, love). Your clothes – whatever the price tag – will repay you with years of service.