Well, many people have grown - and continue to do so - with only HPS (high pressure sodium) lighting. And the same is true - but to a much lesser extent - with MH (metal halide) lighting.
But that is, in many ways, a question that really requires some clarification on your part. Are you growing (or intending to grow) in just one space, going from seed or purchased clones to harvest all in that one space? Or do you plan on having a separate area for vegetative growth (or, at least, for the germination and early seedling growth)?
There is certainly no technical reason why you cannot use one type of light all through the plant(s) life cycle. (Assuming that one light is adequate for flowering, lol). But there might be some practical reasons why you would not wish to do so. Some people prefer to use illumination of a higher overall color temperature (6,500K or even 7,200K) during the vegetative phase because it is generally believed that this promotes shorter, bushier growth. They then switch to a light source that is of a lower overall color temperature (2,700K or thereabouts) during the flowering period (or, sometimes, immediately after the "stretch" - the period of rapid vertical growth that occurs during the first 40% of the flowering phase). I have done both; it is really up to the individual grower whether or not to have separate types of lighting for each phase. Then, too, consider that one can generally use less illumination during the vegetative phase. If you have small plants in small containers, you might be able to place them close together and, therefore, only have to illuminate a significantly smaller footprint. This can (will) save the grower money because he/she is using less electricity. Also consider that you want your grow space to be full of bud at harvest time - but if you allow too much growth during the vegetative phase, lol, when that stretch period that I mentioned takes place you'll most likely have a "train wreck" in your grow room. Overcrowding can be just as detrimental, if not more so, to a good harvest than under-filling the space can. Some people will use lighting that provides far less illumination (even just a few CFL) for their plants' initial growth. Others... If one is running a perpetual setup, where they are adding a few plants each week or two and harvesting the same number, one might wish to have strong lighting in their vegetative area.
Having a second space is very helpful, even if it is a lot smaller than one's flowering area.
You know not what you ask, lol. But, seriously, you need to figure a few things out. How much product do you need (if the answer is "as much as possible," that is okay too). If the amount is small, there is no need to build/buy a large grow setup. Then, too, you need to figure out how much space you actually have (or will) to devote to your overall grow area. Do you have room for separate vegetative and flower spaces (and wish to do so)? I'd recommend this, if you are able... Not just because it can be a whole lot more convenient ("Yay! I just harvested. I feel so good. I can't wait until I can start flowering the next round... in a couple months." "Wow, that was a fine harvest. I want to start flowering again! I think I'll clean the flowering area tonight so that I can stick the next set of plants in it tomorrow." Which scenario would you prefer, lol?) But also because, well, if you are purchasing quality genetics from breeders/seedbanks/dispensaries, it costs money. Why keep buying more of the same strain when you can maintain one or more mother plants in a separate area and take/root cuttings whenever you wish to grow more of that same strain? And sooner or later you will probably have a harvest and, later, after drying/curing it, decide that it is your favorite bud, ever. The vast majority of strains on the market today are hybrids instead of IBL (inbred lines). That means that you can expect a good bit of variation, even from seeds that came out of the same breeder's pack. If (when) you discover that special something, you really want to know that you have it growing safely in your mother "room," ready to provide exact clones whenever you wish.
Once you have determined these things, then you can ask yourself, "How much illumination do I need in order to adequately light this space / these spaces?" At that point, you can decide what type of lighting - and how much - is best for your individual situation. There are also some other factors which play a part, such as the height of your grow space(s), your ambient temperature, how well you can deal with heat (this is not so much a question of light type as it is of the overall amount of wattage - lots of lighting watts create lots of heat), et cetera. In case I did not already mention it, your BUDGET is an important thing to consider, lol.
HPS is HID. HID is a broad category. The letters stand for high-intensity discharge. That category contains HPS (high pressure sodium), MH (metal halide), and also a couple of others - such as MV (mercury-vapor) which are of no use in the grow room whatsoever. People use the term HID in the general sense, and HPS (or MH) when they are referring specifically to that type.
I have helped people who have never grown before get set up with 400-watt HID setups (and, occasionally, 250-watt or even less). They were mostly pretty happy and did not feel the need to immediately upgrade OR end up feeling hopelessly overwhelmed. Many 400-watt electronic (aka "digital") ballasts are capable of using either HPS or MH bulbs (not at the same time, obviously). Many of them can also be dimmed - meaning the grower can dim their 400-watt bulb to 250 watts in output, switch to a 250-watt bulb, or both. This can be helpful; the grower might be comfortable with the heat that 400 watts produces in the cooler months, but be unable to deal with it during the hotter part of the year and such a setup allows for him/her to continue to grow. It is generally a good idea to reduce the grow space when reducing the lighting... A small light in a (relatively) large room is a waste - some of that light will fall beyond the point where it is intense enough to be usable, and if the walls are close enough (and painted flat white or otherwise covered in reflective material) they can reflect the light that would otherwise escape back towards the plants.
There is certainly nothing preventing you from jumping in with 1,000 watts (or even much more) of lighting, lol. But I recommend you start with a reasonable sized grow and a reasonable amount of lighting. If you have never grown cannabis indoors before, your first grow (or three) will be a time of much learning indeed. I just used the "400 watt" scenario as an example, but I would not recommend going with more than 600 watts initially. And I am not saying that HPS is "the" best light - or even the best light for you. Again, it was just an example.
You could spend a long time reading in these forums, lol. Not just about lighting, but about all facets of growing cannabis. That time... would NOT be wasted
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