Computer repair deduction on item expensed

Self Employed. Home/Business:

Following this piece of info on TT22: If you make an improvement to your business space or equipment that increases it's value or lengthens its life, you cannot deduct the full cost this year. Instead, you should write off the expense over several years. 

How?

Computer purchased in 2019. It is being expensed from previous years. 2020, 2021. 

Repair was $1000. 

How do I expense the new expense 🙂


PS Clicking on the improvement links takes me to examples like adding a fence, paving a driveway, etc. to property.