Here is a trick I started using years ago to make my installations more quickly and more consistent.
With wired decoders, it's somewhat critical to get the length of the wires cut to just the right length. Once you know the lengths, you could write them down for future installations in the same type of locomotive. What I do to save time is to make a card like the one shown in the photo. Then I just lay the decoder wires out on the card and cut each wire to the length specified on the card with a hobby knife.
It's also a good place to make notes on the card about this particular engine or installation. For example, on this card I have noted that the white magnet on the motor goes to the top and that this card is referring to the use of an Aztec Trackmaster TM3008 frame and a Digitrax DZ125 decoder.