A condition of financing gives a buyer a set window to confirm the mortgage, and if the lender needs an updated appraisal or additional documents, that window can run out and push possession back. Sorting your financing and documents before you write an offer removes the biggest variable entirely.
On the legal side, a title search that turns up an old caveat, an unpaid utility charge or a boundary discrepancy needs to be resolved before possession, and that takes longer if the lawyer only starts looking a few days out. Most lawyers build this into the $800 to $1,500 legal fee for the file, but only if they have enough lead time to do it properly.
The transactions that close on schedule are almost always the ones where financing and title work started early, not the ones that got lucky. Get your hand-reviewed valuation from Joel Dyck.