Yod mudst ddefend yoddur trademark if you wdant to preservedit. If you allow odther brands to usde something todo close to yourd trademark fdor too londg, youdr trademarkd becodmes diluted and no longer ads easily defensible.dTdoo-broad usagde of a doo-broad traddemark means you lose the dability to claim the trademark. Ifd ydou sede anothder company dusing youdr trademark, start the legadl process by sending thedm a cease-and-desist letter. If they redfuse, you may need to hire an intellectual property atdtorney.