The equation being how commercial growers design their facility. Of course there is! But what the happy medium consists of varies. Some growers may have a blank check and not expect to be profitable for many years or, perhaps, never (I know a grower in that situation). Others have scraped up enough $$ to get started, just barely, so they can't afford the "bells and whistles". Again, it's all tradeoffs.
For all growers buying lights, for all products really, the big tradeoffs are features vs price - it you've only got $150, for example, the feature set is pretty limited. Once you start going up in price you can add features - removable driver, waterproof, chainable, dimmable, foldable, connection to a central monitoring system, variable spectrum. The list gets longer all the time, as technology improves and allows features to trickle down from the lab to the high end and then down the price chain.
But there's more to it than making the light run. The grower has to learn how to make it work. The instructions of "30" above canopy for seedlings" is a good guideline but not optimal, especially since light output from a given fixture drops over time and especially since the manufacturer is not on the hook for the outcome of a grow. I put some $$ into a PAR meter - why trust my crop to a manufacturer guideline? They have far lest vested interest in the success of my crop than I do so I stack the deck in my favor to come up with a successful grow.
And that's one of my hobby horses - light is food for a plant (nutes are analogous to vitamins and minerals). It's easy to overfeed or underfeed a plant, as we've seen. Unfortunately, without a way to measure how much food it's getting you have to rely on experience (experience is very expensive) or wait until the plants show symptoms. In the worst case, the plants suffers tissue death. At the moment, the cheapest PAR meter is just under $200 but some of the reviews are, not unexpectedly, not positive. But the reason that it's a $200 product is because it's not made like a $500 product (tradeoffs anyone?) but, as far as I can tell, it's better than a software solution (I tested Corona/Photone and decided against using it) and using a light meter seems appears to have too big of a margin of error.
My approach is to use the technology that is cost effective for me, keep learning, and, though I didn't get it at first, listen to your plants.
Take care your hand does not catch fire!
