I have read that you need to frequently repot Basil grown indoor.
Is that true? Why? What is the recommend repotting?
You don't have to repot it, but if you use a lot of it, it might be worth giving it a bigger pot after a week or two of bringing it home. Done in spring, the roots will get larger and produce more stems and leaves, but either way, Basil is essentially an annual plant and will eventually need replacing. Even repotting in summer or autumn might encourage more topgrowth for you to use, but personally I just leave it in the pot it came in - the windowsill it stands on is not wide enough to take a bigger pot anyway, and I don't use a huge amount regularly. Some instruction here as to how and why https://homeguides.sfgate.com/repot-storebought-basil-95775.html