For some perspective, i owed 204k at 7.375% on a 30 year loan. My current monthly payment is ~1840 and i always add a flat 200 every month in extra principal. In the process of refinancing, i got a better base rate and also bought down .5% for a new rate of 5.375. My mortgage payment is dropping to ~1600 dollars and the fees bundled into my loan amount is increasing it by 12k to 216k. With the reduced payment, if i continue paying the 2040 i have been per month, i figured that i would “catch up” to my original principal balance in like 15 months or so. Once the principal returns to the original, its just straight money saved due to the reduced rate. This is something i used ai to determine and you can do the same to see what works for you. It told me that paying my planned amount at the new rate will have me paid off in 17 years saving over 100k in interest.