Entering light goods (which are also used privately)

Adjust the professional percentage. That's what it's there for.

Estimate how many kilometres you will drive in total for each year (estimate, eh) and then estimate how much you will drive professionally. Then you'll know +-.

It's never an exact science, of course, unless you do some tracking or something.What do you mean by tracking? You'll always have to indicate whether it's private or professional use, won't you? I heard from a colleague that he tried that but stopped after a few days. It's impossible to keep track of every journey, you'll forget after a few trips! He used software on his mobile phone, but you still have to do it.

I would say estimate and then make sure you can prove something if you are checked. I myself drive to customers, which is different perhaps. I show my diary during checks, my sales invoices to customers, and as an electrician, it's quite difficult not to visit customers ;)

It's still unclear to me how to enter my light goods vehicle as an investment when it's used 90% for business and 10% privately.

Thank you!

You can simply book your light goods vehicle as an investment, so in box "4 Cost categories" choose investment and then you can set the professional use percentage to 90%.