As one who specs all kinds of such things professionally - Velux is sturdy reliable kit; and as so many have said - the value isn't just the fact they can do what you asked the first time (and that is way more than is advertised/on the website!); it is that the whole product range is really well sorted, and supported.
So, years later, you want a new gasket for a thing you has installed 14years ago? No problem. We are having some of the tiles replaced, can we have a new flashing kit? of course. I fitted it then, but would like an automated blind now, due to xxx. No problem; we can also... probably motorise the skylight if you wish.
One of those products, and manufacturers, who do things properly, stand by their products, with kits to support pretty much any aspect of/ installation idea one may need, and with support for the long-term: you get what you pay for, in the best sense.