Lightweight backpacking is worth it every time you hike wether it is for a week, a week-end, or a day hike. The less weight you carry the easier it is to hike. It's easier to walk to the grocery store than it is to walk home carrying the groceries!
Start your quest toward going light, by looking at what you carry now. If in doubt...leave it out. Did you use it on your last hike?
For example, I used to carry enough first aid gear to open a field hospital...triangular bandages, splints, a variety of ace bandages, etc...none of which I ever used. Leave out extra clothing, socks, t-shirts, undies, "clean stuff for town". Remember those Swiss Army knives with all the option blades, saws, leather punch, and cork screw? if you start with new batteries in your flashlight or head lamp or camera, do you really need to carry spares?
Look for lightweight clothing right in your closet. For example, a lightweight wool sweater and a thin nylon windbreaker or shell will be lighter, less bulky and even more efficient than a heavy weight sweater or a heavy weight fleece. (!00 weight fleece is a good weight).
When you find yourself thinking, "Well, I might need it in a pinch and it doesn't weigh much"....leave it at home. An ounce here another there, soon adds up to a pound.
Start next by looking at the weight of the pack when it is empty. Some packs empty can weigh 6 pounds. Consider next the weight of you footwear. I have some nice pairs of rugged leather boots with thick vibram soles that I will never hike in again, but are nice for work projects outside around the house. I only hike now in low cuts, "trail runners".
Hike in the hills and mountains nearest to you whenever you can. Think carefully about your gear and soon your experience will help you decide. When you return from a hike look carefully at everything you had in your pack. Did it work well? Did you use it? Did you need it?
Two things hikers do all the time....revise the gear list...plan the next hike.
BTW State Parks and State Forests are great areas to hike in. For example, outside of Steamboat Springs CO, is Zirkel Wilderness Area of Routt State Forest...hiked a week-end there. Beautiful scenery, never saw a soul. Another week end, my wife and I hiked in a National Forest that borders on the western side of Rocky Mt. National Park, CO. Never saw another person, only wildlife and wonderful mountain scenery.