Oh you definitely have to vent but you do not necessarily need a honking inline fan. If you don't have odor control issues (I do) or if you use an ozonator type odor control then you can use a small duct vent ($25).

The bulbs will last 7 - 10 years. You probably need to replace them by 7 but I imagine that the tech will have moved so much that you would probably upgrade sooner. Or just add arrays to your grow.

Some people build their own. I don't have the patience for that plus I hate getting shocked. I'm looking at pre-build racks designed for horticulture ops. Key seems to be wave length / spectrum. The crappy lights do not provide sufficient spectrum for flowering. You need a good percentage of the emitters putting out 660 nm which is in the red spectrum.

It is worth noting that you can not evaluate LEDs by looking at lumens. Plants don't care about lumens. They care about wavelength. So the HID lamp puts out a ton of light that the plants just can't see. So a lot of that light is wasted energy.

Good questions.

I'm not there yet but I'm getting closer. Moody - when you are you going to kick off your grow .

Peace.