What size pipe do use to fix a sprinkler leak? got a leaking pipe on my front lawn from so i cant put my automatic sprinklers on what sixe pipe and other things do i need to fix it?

All good points, but one of the easiest ways for a home owner to repair, once u know the size, is get whats called a "slip fix" and coupler in the appropriate size. It can be moved easily and to the necessary length needed with ease. Just check at your local hardware/irrigation store and they will set you up

The pipe size that you already have in the ground dictates the maximum water velocity or GPM you can effectively use at any given point in your irrigation system. If you have a considerable distance to run your irrigation system then you can up size your pipe from the point of connection to reduce friction loss through the length of pipe. But, this will not increase your pressure or GPM. It will only allow you to carry the current pressure & GPM further distances. But, you should also be aware that if your running pipe up hill, you will loose about .4 pounds of pressure for every foot you go up hill. And you will gain the same amount going down hill. There are some professional resources that you can research to help you design your irrigation system. Usually your local plant nursery will have the books and/or info you'll need. There are also several options in repairing pipes. This of course depends on the type of pipe you have. Your local home center or hardware store will have the options available for you.

It is probably plastic pex tubing and you can splice in a piece where the leak is, but you need a special tool to expand the tubing to put in the fittings or couplings ask at your local hardware store, they may have one you can barrow.