Depending on your situation I think it's a good strategy, but getting players at a young age and keeping them longer has benefits too, for merchandise income for example. You'll get most of the extra costs of buying younger players back with the increased merchandise profit. However, if you are short on cash and need to invest in your arena first, I think it's a very viable way to manage your team. I'm doing the same, though not specifically with 1 year between each player. I just keep looking on the TL for players around 28-32 that are good value for their money and try to get some steals, who I can sell at a profit or for the same value after using them for a season or longer.