Okay, let's say you decided that bathroom or kitchen is in dire need of an update and you feel reasonable confident that you can do this project as a DIY adventure.......where to start? Well, with 30+ years in the design and construction profession, I can without a doubt tell you the first step is a plan of action or in the professional parlay a program.
Success of any project is directly proportional to the planning that goes into it. From the scope to the budget to the new construction and finishes......it all has to work together. Believe me when I say that a partner, wife, girl friend or family may tolerate a week, maybe two weeks without a bathroom (as long as there is another one available) or a kitchen (eating out can be fun for awhile but it gets really expensive), but much longer and you're entering a wilderness you don't want to explore. A month, a coldness will settle over your abode. Two months, someone is going to be committed or arrested. Three months, bodily harm or divorce become very viable options instead of just fantasies. Four months or longer, the odds of finding Jimmy Hoffa are better than the authorities finding your body.
Step 1 - Define your scope of work. Are you just going to refresh the finishes or are we talking new fixtures, new elements (shower instead of tub, new cabinets, new appliances, etc., etc..).........the extent of your project will define the elements to be considered as far as budget, schedule and whether or not you'll need permits and/or sub-contractors. Write this out, it becomes a living document and guide to keep you on track.
Step 2 - This is the fun part. Define what you want to achieve, this is the "dream stage". Cut out or down load examples of finished projects that you like or that have elements that you want. Incorporate this into your Scope of Work.......remember, I said it was a living document and you'll be going back to it time and time again.
Step 3 - Now we hit a critically point in the planning where you have to determine do you need professional help in pulling this all together or can you do it yourself? Do you need help with the plan (construction documents)? Do you need permits? Do you know about the building code issues and what is required to be included in your project? Do you know about estimating and developing a budget........it's one thing to say I want to spend $15,000 max, it's entirely another thing allocating that $15,000 into all the various elements that are included in your project.
In the professional field we use a process to insure that projects are accurately designed and costed. In short it usually runs like this; scope and project budget, conceptual design and rough estimate, reconcile back to scope and budget, design development and refined estimate, reconcile back to scope and budget, construction documents (plans, details, specs) and final estimate, reconcile back to scope and budget.......it's a dance of experience, knowledge and expertise that results in a finished package that reflects the client's desire and budget into a concise package of biddable information and direction for the contractors bidding and construction services.
Of course you wouldn't use this exact process in the remodeling of your bathroom and kitchen, but the principals are the same and quite honestly, this is the point where most average DIYer's get into trouble. This is why I highly recommend that the average DIYer get professional help from outside to walk you through this stage. An Architect, an Interior Designer, a Residential Designer or trusted Contractor can help you through this stage. They can help you get the most "bang for your buck", avoid the pitfalls of surprises and get you off on the right foot. From there you can work out the particulars or elements that will need to be done by licensed sub-contractors by your local codes and the elements that you, as the home owner can do your self.
Look there are times when I will make a road trip on my motorcycle with no plan at all short of heading North, South, East or West......... if a road looks interesting, I'll take it. When I get hungry, I'll stop and eat. When it gets dark, I'll look for a place to camp or for a motel room......when I see something interesting, I'll stop and take it in....in short, I'm like a leaf floating down a stream......where ever the road takes me is where I go.......I don't recommend that approach ever to any remodeling or renovation project.
Plan, plan and re-plan..... unless you have more money than you know what to do with, have a very understanding partner or the better lawyer.