I can only answer based on my son's first completed year - he wore same uniforms and insignias during summer cruise month - during last year he wore navy uniforms and work out gear only on those events that were navy nrotc exclusively.
My son received some of the navy uniforms, work out stuff by mid fall last year and then more for spring training 4 day period in April and had balance of uniforms soon after that.
My son attends VMI - which has their own uniforms for all things, so if you are going to attend a regular college, the uniform thing may be different. I have found the NROTC unit at VMI very helpful and happy to answer any and all questions - before my son attended and during the past year when he was there.
Hope this helps - but there be others on this site that can give you more formal answer.
good luck - larry's mom