Ok.

2015s signed at 3.29, then with my son on the way we “ported over that mortgage to our current house, and signed an additional mortgage at 3.99. No “real transfer costs” cause i was adding to my ledger with the bank.

2022 rates at 2.2% I break old mortgages and sign single mortgage at 2.2%

When I broke the mortgages i paid 10k in fees (fines for getting out early) but overall my total borrowed dropped by ~25k due to the reduced rate of interest compounded over 30yrs

So yes you can renew when you want or hold till term. Theres penalties.