Don't wash them too often:
Denim, especially dark denim, hides dirt really well. So you can actually get away with 4-5 wears between washes when it comes to jeans - as long as you can avoid pesky spills. Washing too often can make your jeans fade and deteriorate faster, so only wash them when they really need it.
Don't wash all your jeans at once:
It can be tempting to get all your laundry sorted in one load - but overloading your washing machine with your jeans can do more harm than good. A washing machine packed to the brim can mean buttons and zips snag and damage your clothes. And without room to move they won't get that good a clean anyway.
Turn them inside out:
Keep your jeans in great shape by turning them inside out when washing and drying. This protects the fabric from damage from zips and buttons, and can also help prevent fading.
Separate light and dark garments:
It's not unusual for dark denim to bleed during washing. Prevent damage to your other garments by washing your jeans before you first wear them, and washing them with other dark colours only.
Check your settings:
Choose a gentle cycle with cold water to keep the life in your favourite jeans. Cycles that are too rough with cause denim to fade and lose shape more quickly.
Use an anti-fade detergent:
Shop around for a detergent that boasts anti-fade properties to keep your indigo and black jeans looking new.
Hang them out to dry:
Too much time in the dryer will shrink and age your denim. To get the most out of your jeans hang them inside out, or dry them flat. If you must use a dryer, take them out while slightly damp and leave to air-dry to minimise any risk of damage.
Pull them into shape:
To really take care of your jeans, lay them flat and ease them into shape while still damp. Laying them flat to dry like this means they'll fit like a glove when you pull them on.
Keep it cool with the iron:
Avoid exposing your jeans to too-hot conditions if you want them to last. A warm iron with steam will keep your denim happy.
Hang - don't fold:
Jeans will stretch in places over time, so if you fold your jeans all the time the creases will become permanent. Keep your denim in shape by hanging your jeans instead of folding them when storing.