The question is, how will it manifest...
This is actually quite easy to answer: very much like it does here on Earth.
You have 4 basic tech levels, at any given time:
Cutting Edge: This is the highest/newest, and often it is also more buggy being the most recently developed and has not undergone the true "play-testing" yet. (Being used by millions of people on a day-to-day basis; there really isn't any comparison to that sort of testing.) But it is also generally the "coolest" in terms of capabilities, luxury, etc... For the most part only the super-rich, military (but only the newest equipment), high-government officials and the like will have access to this. So, the newest battlships of the fleet will have this type of equipment, the older ships will still have the average tech (see below). Basically, this is either brand-new tech or it is just more refined/capable versions of existing tech: like more powerful weapons of the same size/type, or much better computers.
Average: This is the technology accessable to the vast majority of the populace. Using today as an example, this would include smartphones, cars with computers and advanced safety features, good computers, etc... Most people are familiar enough with this type of technology that it is normal to them to see and use - not that there aren't exceptions, of course (see Out-of-Date and Anachronistic, below).
Out-of-Date: This is the stuff that is, well, a little out-of-date with the current technology. Modern-day examples include: payphones/land-lines, leaded-gas using vehicles, VCRs, etc... These things are generally not used by most people, but there are still some "hold-outs" that do. Also, when we are talking about a multi-system space setting, where worlds don't have constant, regular, and speedy contact with each other, this type of tech will be way more common, and actually the "Tech-level" of many worlds/peoples.
Anachronistic: For whatever reason, there always seems to be those individuals and groups that just don't want to be (or can't be) "modern." The Amish are a great example, so are several tribes in both South America and Africa (as well as other areas, I am sure). The tech-level of such people will be so out of synch with the rest of the populace, as to make them, for all intents an purposes, a distinctly different people/culture - not to mentions seem strange to the more "modern" people. In these groups you can find some seriously low-technologies, like stone-age or similar. In a space setting, it is very easy to imagine that the population of an entire would could using ancient tech like this, probably because they have not had access to sources of higher tech for a long time (including the people who build and work on such tech).
The way these all work together, of course, depend upon the setting and the answers to a few questions: Has there been a concerted effort to limit technological growth? Has there been serious enough upheaval (massive civilation-wide wars, for example) to stop growth? (Which would only be for a limited time, as we just seem to have this drive to go on, even when it doesn't seem like it.) Have there been outside influences, like aliens with higher/stranger technology?
While I am sure there are many more questions that pertain, those 3 are a pretty-good jumping off point, I believe. But basically, unless the setting is so different from "reality" to be nearly unplayable, it will be like now: the expensive/new/cutting-edge stuff with limited availibility, the average stuff that most have access to and understand, the slightly older technology only used by those without access to the normal stuff or those that just want to hold onto what they know, and the much lower tech usually being used by those that actively resist modernization, though there can be other reasons as well.
