Due to the fact, that a Light Saber can cause injuries like a stick, it is necessary to wear protective gear.
Training techniques with a partner requires just light protective gloves (military or motorcycle) and Airsoft-glasses. A cup for men is recommended.
Fighting with reduced speed and light hits requires light protective gloves and a fencing mask. A cup is strongly recommended.
Going full speed but light hits requires better gloves (motorcycle or HEMA-gloves), a fencing mask and a cup.
Not only full speed but also full contact fencing requires good gloves (Lacrosse, HEMA), a fencing mask with back-of-the-head protector, torso-protection (HEMA jacket, ice-hockey protector), elbow- and knee-protectors and a cup.
Each fighter is obliged to get his/her gear for the intended modus operandi. As there are different options, it is not necessary to buy all at once.