Hang up your damp shirts in the summer and they dry pretty crease free. And wear jumpers in the winter so no one can see your shirts. That's the formula that's worked for me, I think I can count on one hand the number of times I've used an iron
Indeed, other options include hanging them in the bathroom when you shower or if you are wearing a suit all day just iron the front. To be honest if I am wearing a suit or travelling first thing I rarely bother ironing as an hour travelling creases the fuck out of even the most ironed shirt anyway.