Creatine is not a "steroid type of thing". Steroids are hormonal. Creatine is a substance found naturally in the muscle. It's very safe and widely used. The purpose of creatine loading/maintenance is to increase baseline levels of creatine in the muscle - i.e., increasing muscular energy.
For this reason, creatine should be taken as directed, and consistently. This is the most important part. The creatine you ingest isn't likely to be used during a workout (and this is why they recommend taking your creatine AFTER a workout rather than before) - it exists to make more creatine available to your body so your body thinks "Oh, I have more creatine in my system, I guess that means I can store more in the muscle."
The reason there's a loading phase with basic creatine is so you increase these baseline levels within the first two weeks, then from then on, you maintain the levels with a lower amount of supplementation. Some say that with buffered creatine monohydrate (Kre-Alkalyn) there is no loading phase, but this has more to do with its absorption rate than creatine's function in the body.
As far as why you can't take it forever, it's a liver thing. Your liver filters out impurities from the blood, and creatine supplementation - because it's converted to creatinine (a waste product) in the GI tract - can put a strain on the liver if it's taken for prolonged (2+ months) period of time. The way to avoid this is cycling:
You have three options:
1. Only take creatine 4 out of every 7 days of the week. This will give your liver enough time to filter out any impurities. On this scheme, you should be able to take creatine weekly without a break - though of course it won't be as effective as daily supplementation.
2. Take a 2 week break after a month of daily use.
3. Take a buffered creatine like Kre-Alkalyn that isn't going to create much waste to filter out.
So to answer your question: Take it consistently. Plan the days when you're going to take it, and take it, even if you miss a workout. You want to increase the baseline levels of creatine in the muscle, and missing days will lower this availability. Consistency is the most important part.