My [2c]:
Something to keep in mind is that you don’t get to see the whole layout either on the forums or in the pages of MR. What you do see are the best views of it. My layout, for example, is only half sceniced and it has a 1:1 furnace right in the middle - I don’t tend to show off the half that is just track on OSB, and I do my best to keep the furnace out of the pictures.
Another thing you don’t see are the results from when the builder was in the middle of the learning curve, or the experements that yeilded less than satisfactory results. My layout has layers of substandard results hidden beneath layers of better results. Allow yourself time to learn and keep in mind that a lot of the learning comes from just trying and trying again. You can get through the learning curve faster by reading and by discussing methods with more experienced modelers (it is rare that you’ll find a model railroader who won’t let you in on his/her secrets).
I urge you to get started. I also suggest shopping where you can get good used stuff as a way of dealing with the cost issue (with one exception - buy your electronics new with a warranty). I shop on eBay and at the swap meets that go with train shows. I figure that I stay in the hobby for less than half the cost of buying everything brand new.
When it comes to time, think about your reasons for being in the hobby. I can only speak for myself, but I’m in it because it gives me a creative outlet in which I can spend the time that isn’t devoted to something else (girlfriend, work, home upkeep, yard, dog, etc.), so I’m glad to spend as long as it takes; if it ever got finished what would I do? I know a guy who is really just interested in operation, so he hired some help and they built a huge layout in a matter of a few months. It’s not superdetailed, but it looks good, and boy does it ope