I was standing in my layout room the other night thinking to myself "You know, I could make this layout twice as big if I were to cut a hole into this door, curve the mainline through the closet and back out into the room along this other wall..."
I had to stop myself. I was coming dangerously close to violating one of my personal rules I established for myself when I started this model railroad: Keep It SMALL Stupid. (K.I.S.S.)
I imagine most modelers find themselves longing for larger layouts from time to time. The advantages that come with more layout are hard to ignore, yet there are also plenty of advantages to keeping a layout small and focused as well. Small layouts are cost less to build. Benchwork, wiring and trackwork goes much quicker which gets trains moving sooner. Smaller layouts allow you to focus your attention on modeling finer details that would just be too time consuming to be considered on larger layouts.
For example, I have spent many, many hours individually detailing and weathering ties on my little railroad. Now that job is nearly complete which is good because I am starting to get a bit burned out on track details and I'm ready to move on and try something new. If my layout were twice as big as it is now, I'd only be halfway through the job and frankly, that would be rather discouraging.
I'm 33 years old and know myself well enough by now to know that I may DESIRE to have a big layout from time to time. However, I also know that keeping the layout small and manageable keeps me from getting burned out which keeps me excited about the hobby.
Besides, I've got a mountain to build, trees and a river to model, buildings to kitbash and assemble, a highway overpass and railroad bridge to scratch build, cars to weather, and much, much more. I've got enough work on my plate to keep me busy for years!