After finding your perfect liveaboard boat, you will probably want to add some creature comforts to make it less like camping and more like living. What gear do you really need? What gear is nice to have? What gear is a waste of space?
To be just camping in a boat, all you need is a place to sleep. This is easy to achieve, as a simple bunk or hammock will meet this requirement.
The next level of comfort would entail adding plumbing for a head with a shower and a galley. Now you can cook, clean, go to the bathroom, and a place to shower; all within the comfort and privacy of your cabin. At this point, you are camping in luxury!
For added comfort, you can add climate control and refrigeration to the boat. Refrigeration will allow you much more flexibility in the foods you keep on board and how long you can keep them for. Your world will expand from "foods that keep" to "foods you want" on board your boat.
Climate control will also make your life much more comfortable. Instead of living in whatever climate you are in, you have the option of controlling the climate in your cabin. No longer is coolness dictated by how many hatches you can open in hopes to capture a cool breeze, or warmth dictated by how many layers you can wear! Air conditioning will keep you cool during the warm seasons and heat will take the bite out of winter. Now living aboard will be a comfortable way of life rather than just a place to live.
I lived for two years without air conditioning in Maryland, where the heat warnings are issued regularly during the summer. I found ways to keep cool, such as staying in the shade and taking cold showers to cool off until the sun goes down and the heat subsides. The dire heat only lasted a few weeks, and the rest of the year was much more comfortable, but it was still a hot few weeks! When Maddie moved in, I installed air conditioning in the boat, and what a difference it made! Those hot weeks are now comfortable, just like any other time of year. I don't like most electronic systems in a boat because of the maintenance required to keep them running, but this creature comfort is makes life aboard amazing!
At this level, you now have a floating home with a place to cook, wash, go to the bathroom, and keep your food; all in the comfort of a climate controlled boat. This will give you a comfortable place to live with the basic necessities. Having lived in a boat with varying levels of systems, I can tell you with certainty that these few systems will give you a comfortable living situation with as little complexity as possible. Meeting these basic needs will grant you comfort aboard and allow you to spend more time on projects you want to do or activities you look forward to, rather than fixing complicated systems that bog down your life aboard.
If you feel the need to have more systems in your boat that you are living in, you must be willing to deal with repairing these added systems. Now we are looking at "wants". The most common want on a boat is a TV. TVs provide entertainment without requiring much space, a very small boat can become a comfortable man cave by adding a large flat screen TV! The problem with a TV though is they need to be connected to something, and all of these components begin to add up in complexity on a boat. Imagine a home entertainment system with all the wires hidden away behind the cabinet in a house; where are you going to fit all those components and hide all those wires in a boat?
Another common "want" category is kitchen appliances. Things like dish washers, toasters, microwaves, ovens, blenders, ect. are all items that are nice to have but not crucial to have in a boat to survive. These appliances take up a lot of space and will eventually break down over time. The more appliances you have in the boat, the more you will need to fix in the future.
If you find that you absolutely need an appliance on board, feel free to add it, but be aware that you will need to maintain it if it breaks down in the future. I added a toaster in our galley and wedged it a cabinet to keep it from falling over because it is very convenient in the morning to make toast in a toaster instead of on a stove top.
One important point to keep in mind when choosing an appliance is to keep glass to a minimum. A large glass blender will become a large amount of shattered glass in a boat if a large wake knocks it over! Keeping glass components to a minimum will minimize the risk of having broken glass inside the cabin.
The last category of "waste of space" tends to be appliances or amenities that consume outlandish amounts of water and electricity. On a boat, your resources are very limited. If you leave the faucet running in a house, the water keeps flowing and you end up with a higher water bill. In a boat, if you leave the faucet running, you end up with an empty water tank. Appliances such as dish washers and clothes washers take up a lot of space and consume extraordinary amounts of water! This means that you will have to fill your water tanks more often because these machines are sucking your tanks dry.
While a dish washer sounds like a nice idea in theory, think of what it will actually offer. How hard is it to wash the dishes in the sink? Especially when it's only one or two people who are living in the boat. The dishes take a few minutes and very little water to wash by hand in the sink. Then they are set on a drying rack to let drip and air dry, consuming no electricity and not much space in the boat. The alternative is to have a dish washer in the boat which will consume a lot of space, and even more water and electricity. When all the dishes are dry and put away, the counter space can be re-purposed. A dish washer, on the other hand, is always there. It will occupy a lot of space in the boat and that space can not be used for other purposes.
A clothes washer is another item that sounds convenient to have in a boat, but once again, they take up a ton of space! These machines will draw a lot of water out of your tanks and produce a lot of heat inside the boat as they run. The worst part is these machines are not used frequently. If you do laundry once a week, that means that this large machine is occupying a lot of space for the other 6.8 days of the week! It is much simpler to take your dirty laundry to a shore side laundromat and have your laundry done there. If you absolutely need to do your laundry in the boat, there are very small and efficient manual clothes washers available which wash your clothes very well.
Not only do these large appliances take up a lot of space and consume a lot of resources on board, they also cause additional headaches. I have been in a lot of boats where the owner tells me that the clothes washer kept breaking and they stopped fixing it a few years ago. This means that for the past few years, there has been a large box in their boat that is wasting a lot of space.
When you are looking around for the proper liveaboard boat, consider space to be a very valuable resource and everything in the boat is occupying this space. Is the item you wish to bring into the boat worth the space it will take up? If it is not worth it, you will be much happier not having to deal with these systems when they eventually break down.