Is it bad to levave a soldering iron plugged in?

[Sam Spastic]

I love my Princess. 25W Iron clad. Back in the day we left these on all day.

[tkamiya]

When I did this for business, we had all soldering irons on during business hours.  These weren't today's temperature regulated types.  It was during 1980s.  We never gave it any thought actually.  They were all Hakko types and they lasted just fine.

[TomS_]

I leave mine on sometimes for an entire day if Im working on something big or doing stuff frequently.

If I know Im probably not going to be using it for a little while I'll at the very least add a blob of solder to the tip so that its not out in the breeze. If I dont think I'll be using it for a longer while then I'll probably turn it off (always after adding a little more solder to the tip).

Its a Hakko FX-888D and heats up to useable temperature in about 20 seconds, so I really dont care whether its on or off at the instant I need it anyway.

I also put the iron back in the holder without cleaning the tip, so that what ever solder is left on there hopefully prevents the tip oxidising too much. I only clean it when I take it back out to use it again. I use a brass sponge/wool, rather than a wet sponge, as it seems to clean around the entire tip in one go instead of having to wipe multiple times at different angles. A couple of jabs and jobs a good'un. Brass sponges seem to last longer too and dont get all manky.

I dont use it every day, but after a couple of years of semi frequent use like this my tips are still looking and working just fine IMO.

[Jester]

The super fast warm up of Metcal, minimizes this problem, turn it on and off as required.