You can't hoard surplusses year after year. Each year your team will have to fit under the $ 1,000 budget cap twice, - after new contracts are signed and by the time the free agent auction is over. After contract signing time, you need to be at least a little bit under the cap to allow yourself some space to sign a few free agents. At the end of the free agent signing auction, you might as well be as close to 1,000 as possible as "you can't take it ith you".
It is possible for a team to temporarily be over the cap due to an inseason trade for Albert Pujols for instance, but when contract time comes up, and the free agent auction is over, you have to be back to 1,000.
The lessons there are be careful before you trade for a guy with a big five year contract on his back. Theoretically, Johan Santana might carry such a contract today were the league going for a while.
Also, there will be good free agents in every draft class so don't spend everything at contract time. Some guys like Santana, Pujols , etc will have their contracts expire and will be released to free agency because they are either too expensive, or a team wants to rebuild and use the contract money freed up for 4-5 prospects (Josh Vitters, Jacob Turner types.).