hledger: track if BahnCard was worth it

In November 2021 I got offered a 30€ discount on the BahnCard25 from the Deutsche Bahn AG. Some time ago I cancelled my BahnCard because I wasn't using it enough to justify having one. With a 30€ discount I should have no problem getting the remaining 25.70€ of value back.

But I wanted to track this. I am using hledger to track all my expenses and assets.

The ledger statement for the Bahncard looks like this:

2021-11-24 BahnCard 25
Expenses:misc:Bahncard                     €25.7
Assets:Checking Account
(worthIt:Bahncard2022)                     €55.7  ; full price
(worthIt:Bahncard2022)                      €-30  ; discount

And one statement of the travels looks like this:

2022-01-04 Travel S->KA
Expenses:Travel:Deutsche Bahn             €10.65
Assets:Checking Account
(worthIt:Bahncard2022)                    €-3.55

Result of my current balance:

hledger reg ^worthIt:Bahncard2022