An address finder is preferable
This tip is valid only if you don’t have an Address Finder field and keep the traditional address fields (street, city, state/province, country, zip). It will simplify the checkout form a little. Please see best practice #123 for that better solution.
Complex checkouts create abandonments
From the data I found, about 11-12% of people quit because the checkout is too complex / long, so this helps a bit.
According to Baymard’s data however, a whopping 26% of users abandon purchases during the checkout flow solely because the checkout flow was too long or too complex. Now they don’t say exactly what too complex means.
Fewer fields is better
The average store had 14.88 checkout fields in 2016, 12.8 fields in 2018, and they recommend only having 6-8 fields for a guest checkout (including the credit card fields). So, fewer fields is better. And my assumption is that having to fill fewer fields is almost as good as having fewer fields altogether.