There are reversible and irreversible decisions. Don’t get stuck in analysis paralysis on reversible decisions. Just do and redo in case of failure. Save your time for the irreversible cases. This is where you want to be really confident in your decision. You can only cut a plank once. If it turns out too short, you cannot add a piece to it later. Measure twice in this case before cutting.
In reality, reversibility is on a spectrum. Cutting a plank might be irreversible, but you can get a new plank and try again. The parameters that decide the reversibility of this problem include availability (are there new planks nearby), values about waste (how do you feel about wasting fine planks), cost (can you afford a new plank), time constraints and wasting time (are you on a deadline and is the nearest store an hour drive) and possibly others. For someone with an unlimited purse and who enjoys road trips, it is fine to make a round-trip of two hours to the store and buy a new plank. The decision is reversible. To the person that is collecting scrap wood for the construction of a shelter he has to sleep under that same night, the decision is irreversible.