This question originally appeared on Quora. Answer by Laurence Shanet.

There is a huge variation in this area, and the term "professional" encompasses a lot of players. At the very least, there are about 1500 players each on the ATP and WTA computers. For those competing below the main tour level, the costs are quite different, but I will address the question from the point of view of an active main tour player (let's say top 50 or so), rather than one who goes to satellites and/or challengers. At this level, Keith's estimate is not at all unlikely. Clearly, the lower ranked the player, the less he/she can afford to spend on trainers, travel, and other expenses. Also, if a player employs a coach, this doubles many expenses, as the player is expected to pay for all of the coach's travel expenses as well.

Travel - This is  typically between $50,000 and $150,000 PER PERSON , depending on which events are played, where they're located, and how fancy the accommodations. Here, things like level of hotels used and whether the player flies economy, business class, or private can have a huge impact on the bottom line. Also, some tournaments do pay a per diem to cover some or all of the hotel costs. However, this amount varies by the tournament and by the player. It also varies greatly based on whether the player has to pay for other team members (coach, trainer, physio, spouse/partner, etc.). Also, some tournaments pay lucrative guarantees to the marquee players that helps offset expenses and then some. In fact, these guarantees are often larger than the prize money on offer.

Food - While this is subsidized in some cases by the tournaments, there are still lots of costs when you're not actually at the tournament hotel, or on the tournament grounds. And again, this varies greatly by how fancily you like to eat. Costs can be anywhere from $5,000 a year to $30,000 a year. Again, this is per person, and is multiplied by the number of people in the entourage, since the player is expected to pay for coach, trainer, physio, etc.

Coaching - The starting salaries for professional tennis coaches at the ATP main tour level are probably in the $50,000 per year range, plus any expenses. However, most have bonus clauses in their contracts based on the player's performance, and top level coaches are often paid as a percentage of the player's earnings (10-15%), so the cost of employing one may be as high as $1-1.5 million for the top few players. Most fall somewhere in between. This doesn't include the additional costs the elite players pay out for trainers, physios, additional coaching, etc.

Stringing and customization - This varies, depending on how far a player gets in each tournament, but can be  anywhere from $5,000 - $40,000 a year . While most pros at least get their racquets free, they generally have to pay for stringing. And some of them pay a hefty annual sum to a private stringing and customization service to keep their gear consistent and in tip top shape.

Other expenses - In addition to all of the above expenses, there are quite a few additional things that can slip through the cracks. They include ground transportation within the destination cities and transfers, tournament penalty fees, fines, clothing and additional equipment for non-sponsored players, medical expenses and massage.

So in the end, a top 50 player will spend anywhere from $100,000 - $2,000,000 in expenses, with many in the $150,000 - $500,000 range.

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