But not your clients, right?  Because they always call you first before making tax-related decisions.

Solar is a worthy cause, but a $30,000 system is priced at $40,000 as soon as a $10,000 tax credit is offered.  I just had a client who bought one and then converted a chunk of IRA money to a Roth, so that his tax liability would use up the credit.  Not something I would have suggested, but in this particular case I wouldn't condemn it.  Then there is the client with a $6,000 carryover credit and no taxable income for the rest of her retirement life.