brand new all-leather indoor balls must be "broken in" first to achieve optimal grip before use in competition. The abrasiveness of asphalt and the dirt and moisture present in an outdoor setting will usually ruin an indoor ball within a very short period of time, which is why an indoor/outdoor ball is recommended for recreational players. Outdoor balls are usually called outdoor rubber basketballs & they are commonly made from rubber to cope with rougher conditions, and they need to be filled with more air to retain a suitable level of air pressure in colder weather.