Even if you plan to stay in your house long-term, buying the equipment outright risks getting stuck with outdated technology. It seems there have been a lot of advances lately in solar panel technology, so if you had bought panels a few years ago, they would not be nearly as efficient as if you bought them today. And if you bought them next year...
The retail price of electric power basically never decreases. Therefore, if a solar purchase makes sense today, it won't be regretted later. If it doesn't make sense, i.e. because the cost of financing the loan is greater than the projected savings on electricity spending, then it would be reasonable to wait for higher-performance panels.
Sure, but if I can lease today's equipment for a short time, and then upgrade to tomorrow's equipment, and get the better performance, that might work out in my favor. I'm not out the full cost of the equipment today, needing to amortize that over 15 years.
You're paying for the full cost of today's equipment either way, the difference is that with the lease, once you reach the end of the lease term you have the choice of either throwing it in the trash or paying the cost of a new system to keep what you've already paid for once.
