It depends on the pro.
Solve will prepare their bats properly, play them in IV the nets and have a favourite they try to keep going for as long as possible. Others will use a bat until it breaks, then take the next one or the wrapper and use that until it breaks.
I beleive Alastair Cook likes do play his in and keep them going as long as possible.
In one of his books Freddie Flintoff said about when he broke his bat in the 2005 Ashes, a load of brand new bats were bought out to him, and having never used any of them he didn't have a clue which one to pick, so he grabbed the one nearest to him and took it out the wrapper!