Having no plan is a formula for losing money on a job. If you plan your jobs, you can easily plan your business.
There is a procedure or plan to accomplish this. You would not install a system without a plan. If you do, then you run the risk of putting the wrong equipment in or having to run to the supply house to pick up forgotten parts or having an incredibly sloppy job that takes longer than the budgeted hours. Having no plan is a formula for losing money on a job.