1. Avoid over-washing
This is a common error that's easy to make if you're not paying attention at the end of a busy day. It is so much easier to pop items into the clothing hamper than it is to hang them and put them back into the wardrobe for a second, or third wear before they go in the wash, but there's a cost in the life of the garment. Washing does break fabric down over time so while you won't notice it day-to-day making sure clothing isn't over washed can give garments extra years of wear.
2. Follow care instructions
It's tempting to let the washing machine tell us that it can be "delicate" and manage wool and silk but these settings are not always as gentle as we might like to think. For delicate fabrics, particularly wool and silk, hand washing (gently and separately with the appropriate detergent!) is the safest option AND while it is more time consuming it will give your garments the best chance at a long life.
3. Store garments correctly and ready to wear
Some clothing pieces are best suited to folding and others are better suited to hanging. Make sure you have your clothes stored carefully and appropriately for the piece. Knitwear for example is best folded v.s hanging as the delicate nature of most knits means that hanging risks the shoulders stretching out. Most items enjoy a cool, dry place, out of the sun and be sure to watch for dust accumulation over time too (yes, that means vacuuming your wardrobe and wiping out your drawers when you do your closet clean out.
If clothes are stored correctly and they're steamed or ironed ready for the next wear you'll find getting ready in the morning much easier. Think of it like you're doing your future-self a favor!
4. Transition garments for a second "life"
Where possible some garments can transition to a different use in your wardrobe. Some garments can go from day wear to active wear or lounge wear. Think of old tees and tanks, these can sometimes become sleepwear too! There may be a second life for your clothes which will save them from the donation bin for another year. Basic mending and sewing skills can help with this one too; patch knitwear, hem jeans to a new length for a fresh look, turning old dresses into skirts... one youtube search will give you thousands of ideas for ways to do this with pieces you might have been ready to retire.
Every additional wear is a saving so get creative and you can save money AND reduce your environmental footprint.
5. Purchase wisely
Last but not least make sure you're making wise purchases to start with. Choose quality over quantity and you'll be on the best footing for a wardrobe with a long life.
Hopefully you can use one or more of these tips to keep your garments in usable condition for a nice long life!