Every client is unique, and so is every project. It’s best you treat it that way. This is for your client’s benefit, as well as your own. Treating a project on a template basis is bound to cause problems for you. You either end up overcharging the client, at times making them go somewhere else, or costing yourself. Give it the attention required.
Yes, there are times that you spend time on a proposal, only for it to be rejected. However, be assured that your “serious” clients will appreciate the effort you put in. It will even, yes I say will, open doors for new clients and projects.
Making every project unique not only adds an aspect of excitement, but creates opportunity of further work. Keep record of every aspect, whether in cost, preparations or consumables, as this this will enable you to not only anticipate the consumables for future project, but also allows you to identify consumables to keep in stock. This avoid time wasted running off to the hardware store, as well as the cost of buying littles bags of consumables at a small hardware compared to buying in bulk from a wholesaler. In itself this allows a larger profit at the end of the project, without costing they client extra.
Enjoy every project!