This advice may sound silly, but it will save you time and hassle. Give it a try.
If you’re an infrequent traveler, do a test pack one week before your trip. Leave your suitcase open in your bedroom. Through the rest of the week you’ll remember items you meant to pack and toss them into the suitcase. You’ll also realize you over-packed on other items and edit out things you won’t need.
Before you test pack, put everything you’re bringing across your bed and take a picture of it. This will be useful for insurance purposes if the airline loses your case. It’s also a chance to make a visual assessment and take out items you probably won’t need. Or perhaps to take note that you wear too much black. “This wardrobe needs more chartreuse!” These words I have spoken in perfect seriousness.
If you’re a frequent traveler, keep a duplicate set of everything you need in a small suitcase. Leave it always packed and ready to go. When you get home after a trip, take out only what needs to be washed, and then replace it, zip the case, and store it back in your closet. Don’t go through the hassle of unpacking and repacking your suitcase every time you go on a trip. Always pack the case in the same way so when you’re rummaging in the dark you know where to find the items you need.