Best practises are ideas that aren't requirements, but have been found to be the best way to do something. You may not follow best practises for some reasons (eg, best practises may give a lot of benefits that are irrellevant to your goals) but in general it's better to follow best practises where possible, even if it causes more work in the short term, as usually they cover a lot of contingencies that you may not forsee.
2 pages link to BestPractices:
