Also - if an iron has an automatic shut-off - when the iron is moved, it will heat up again if one did not actually turn it off.
I usually - or so I thought - click the iron to "off" - so I set a cold iron on carpet - and the iron heated up and melted the carpet.
Now DH put an extension cord up so that it is easier to plug and unplug the iron in - and I always unplug it now when I am not using it.