Completely agree with you
@Bertyboy.
When I was first diagnosed, I was given the choose between reuseable or throw away pens. Without seeing them, I very quickly opted for refillable to avoid adding to the plastic mountain and was not disappointed.
They were incredibly easy to refill: just unscrew, wind back, insert filled cartridge and screw back together again.
And, when you go out, taking a spare cartridge or two takes up a lot less space than taking a whole new pen.
My pens lasted for 7 or 8 years. However, I would strongly recommend making sure you have spare pens in case they break. One spare for each type of insulin. If you ever get "odd" readings, changing pens is always an option.
I also had 0.5 unit pens (until I moved to the pump). Things may have changed but at the time, these were only available "for children" which meant they were brightly coloured rather than "professional grey" but apart from that they worked in exactly the same way.