What lights are you installing? UGR (Unified Glare Rating Compliant) lights should be installed otherwise staff and students could get headaches, they should also have a rating below 19 for classrooms and offices especially with computer screens and panels.
You can get up to 7 years warranty including free labour for replacement of lights, so there is no risk to you in replacing them or investing in them.
Are the luminaires your using giving a good light source for the energy your using? Sometimes cheaper fittings are more expensive to run so you don’t necessarily save more. Find the balance between cost and savings. Using cheap products can mean they fail to work and need replacing a lot sooner than other products.