If the case warrants, an opposing attorney may research your background to determine if you have been sued, your professional license suspended or whether there is any other public record information that may damage your credibility as an expert. If you have any blemishes in your background, promptly inform the retaining attorney. Lawyers hate surprises during battle. With sufficient notice, the attorney can minimize or eliminate the effect of the adverse information. Attorneys always need your biographical information to disclose to their opponent.
Litigation is time consuming and stressful, so charge accordingly.
You may have to block out half a day to testify for 45 minutes in a trial since it is impossible to predict when the testimony of a prior witness will end. If you never have sat for a deposition or attended a trial, don't be shy, ask the attorney to explain what you can expect. There are many techniques known to attorneys that can make you more effective in a deposition and at trial. With experience, you will learn them and feel more comfortable. If you have not previously testified as an expert, that is fine.