avoiding trademark/IP lawsuits after software launch

Branding and other trademark-related decisions should be preempted by a trademark attorney's clearance search. That activity is often only considered prior to applying for a federal trademark registration, but another's infringement allegations would be indifferent to your own attempts to protect your allegedly-infringing mark.

Similarly, prior art searches (which should, necessarily, dig up enforceable patents) are often only conducted in the context of one looking to apply for patent protection. After-the-fact research, usually done in response to a cease and desist letter, is sometimes deemed an infringement and validity analysis; i.e., it is performed to validate the complaining party's infringement claims.

An attorney is not "required" to perform trademark and prior art searches, though the fact that attorneys specialize in these areas highlights the potential for pro se errors in either doing the research or arriving at a conclusion therefrom.

Generally, however, you should view attorneys - be they trademark, patent, or other attorneys - as beneficial. Trademark, patent, and other IP-related legal assistance does not have to be exorbitantly expensive and avoiding engaging them is a risk.