4) You will need to have on hand trustworthy plumber tape, small gas torch, solder, flux, plumbing sandpaper, pipe cutter, gas tape (to seal gas line) and maybe some pipe glue. Ask the sales person at the hardware store for a more defined list.
It water line repair is advisable to speak to neighbors and friends regarding the same. If any of your neighbors or friends has had a plumbing emergency and has been happy with the plumber they engaged then it is best to contact the same plumber. Family may also be of some help as far as recommendation is concerned but neighbors are a better option because they will give you details of an agency in the same area as you.
One other common design that is considered "washerless" was made famous by Delta and copied by several other makers. It uses little "cup" seals that fit over springs recessed in the back of the valve body. The springs press these "seals" against the cartridge and regulate the flow through little tapered openings in the cartridge. If you have one of these and it's dripping, changing these springs and seals will usually correct it. Here's a tip. Once you have the cartridge out of the way, insert a phillips screwdriver into the seal and pop both the seal and spring out. Stick the new ones on the end of the screwdriver to help guide them into place. This is especially helpful if you don't have long slender fingers.
Working on the gas lines is also a complex job that only a licensed plumber can handle because it is very dangerous. Small leaks can't always be detected by odor alone, but a licensed professional has the proper equipment that's needed to ensure that you don't have any leaks in the line.
The first step in the replacement project is to turn off the water line repair to the toilet and flush any water that may be in the tank. If you forget this step, you will have a giant mess to clean up! You should now disconnect that water line.
And the way to know what's sufficient? Well, until the work is done an the bill paid you won't know for certain, but this is the best that can be suggested and normally works very well.
Sometimes there can be complications of broken toilet flanges, closet bolts or rotted sub-flooring. If you find any of that in your situation, it will need to be repaired before reinstalling the toilet.