I thon it depends on what you see yourself doing. if you want the router for a few select jobs then only buy those bits and any other when needed. if you do a lot of one off jobs of different profiles then a set is great to have. I have 2 sets a 12 piece 1/4" set and a 24 piece 1/2" set/ I have only used probably 1/3 of the bits . but some of those I couldn't have predicted needing those in time to order them I would recommend buying a small set from one of the main manufacturers that is designed to have the basics . make sure the core bits you use are great quality. you will use them regularly you will probably want a bearing flush trim bit pattern bit (maybe a combination would do) 1/2" straight bit chamfer bit round over rebating bit set I think a medium quality (at least) set is great to have at hand for one off work