As a beginning fly fisher, let’s say you decide you are going fishing tomorrow. The mental process to have, that I suggest, is to ask yourself….what shape is my gear in? How did I leave it from the last outing; yesterday or two months ago……how did you leave your gear?
The efficient way to handle this, is to access your gear the night before. Do you have anything in short supply? Flies, leader material, a piece of often used gear (pliers, nippers, spools of leader material, etc.). This is particularly important if a friend is picking you up at 0-Dark-30. Have your gear together and ready to go. If you are meeting a guide have your gear together. Don’t waste valuable time with a friend or guide putzing around with prep that should have been completed the night or days before. I have fished with people that waste my time and theirs rigging up before we venture forth. Obsessive or not, I consider a half hour + of prep time stream side/lake side that should have been done the night before inconsiderate of friends or guide or both.
So, this brings me to leader construction. Assess your leader for length, taper and wind knots. What type of fly line (Floater, Intermediate, Type II etc.)? What type of fishing? What type of likely fly patterns? Know how to piece together the sections of leader in order to construct the proper length of leader. That means know the proportions of a leader and the knots to join the sections together. (MnFlyFishing)
For the beginner the formulas that are often used are 50%>>>>25%>>>>25% or 60%>>>>20%>>>>20%. Here is a good explanation on constructing leaders for freshwater & saltwater. ActiveAngler
My advice: assess your gear the night before. Be ready. Don’t putz around the morning before and burn daylight. Become proficient in piecing together your own leaders. Having to run to the fly shop the morning of an outing to buy a new tapered leader or a spool of mono is poor planning and again burning valuable daylight. Do not do that with a friend, who was prepared the night before. Part of the fun of fly fishing is fiddling and fondling the gear. However, don’t fumble around with the gear. Get to the point…fish.