Know how much space you have. If you have a large kitchen island, then you can use full size chairs. For home owners who only have a smaller one, they may only use two seats. You should also decide the space that your guests can have. Sometimes, kitchen islands are merely used for decorative purposes rather than practical seating. So if you want to add seats, you should make sure that you have enough space in your kitchen for them.
Islands can "float" as well. Smaller islands used primarily as an aid in cooking or baking can be fitted with wheels and moved around the kitchen as needed to aid in cooking. Whether you consider a floating island will probably depend on what you have installed on the floor now, or plan to install (a soft wood will be nicked and scratched).
In addition to seating 4 (or more), islands today are used to house "luxury" appliances that do not fit in the cabinet structure like a second microwave, second oven, wine refrigerator or even another cooktop. Islands many times are fully wired for electricity and have plumbing for a second sink. The base of an island can be used as a wine rack. The possibilities are almost endless.
Safety First! You are better off without it if you are using up all the free space in the room. Your kitchen should be spacious and you should never feel restricted in your movement - in fact it can be dangerous if you are. Yes, a kitchen island is good to have, but not if your safety and freedom of movement are compromised to accommodate it.
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