definitely not easy by yourself, but the whole process (change, then alignment etc) shouldn't take a decent mechanic's shop more than a couple of hours. I've changed tires on my nearly 200k mile car several times now, and it's usually a few days for the tires to be delivered (in america the mechanic will just receive it) and a 2h appt to get the work done. I'm shocked your parent comment mentioned waiting a whole day at the mechanics'.

My friend does this at Costco, and it takes longer purely because of appt mismanagement and backup, the work itself is quick.