Mortgage refinancing involves replacing an existing mortgage, which may help change the interest rate, adjust loan terms, or access home equity. Potential benefits can include different monthly payments and more predictable terms, but closing costs often fall around 1% to 5% of the loan amount, plus possible penalties depending on the loan. Timelines vary, but the process can take several weeks and typically includes a financial review, an appraisal, and reviewing available options. Challenges can include higher costs and the possibility of not being approved, and outcomes often depend on factors like credit history, income, and overall debt.