If you have four drives you can do RAID 6 assuming your controller supports it.

RAID 0 just puts your data on multiple drives, giving you higher read/write speeds but with no built in redundancy.

RAID 1 is just a copy, you have your data duplicated so that if anything fails there’s an immediate copy. No increase in RW speeds.

RAID 5/6 use “parity data” which operates somewhat like RNA/DNA when going through mitosis. The four building blocks TCGA only connect with one of the other four in pairs of two, so even if you have half the data (RNA) you know what the other half is by logical extension. The difference is that 5 uses 3 drives at a time whereas 6 uses 4, you can only withstand the failure of one drive in RAID 5 but 6 can handle the loss of two.

RAID 10 (one-zero, not “ten”) does exactly what the name suggests, it combines the direct copy of RAID 1 with the striping of RAID 0 to give you double RW speeds with redundancy.

Each one will reduce your overall storage by a certain amount, either because of copying the data completely or taking up space for “parity data.” The only one that doesn’t do this is RAID 0 but you have absolutely no redundancy there and if You’re considering RAID for home use I’m going to assume that’s important to you.