I guess it really depends on your individual circumstances, if you are currently a recreational player looking to turn pro I would assume you are still 'building a bankroll'? If that is the case then I would suggest not making cashouts until you have the roll you require for your chosen stakes.
From then on cash out strategies would vary player to player, some players would base this on profits/results. However is it no better to try not to be results orientated in poker and instead be able to focus on playing a solid game? When you look at it this way and look at how many hours you spend at the virtual felt, would you not want to pay yourself something for your time even when on the negative side of variance?
The best cash-out strategies I have come across on various forums in the passed are based not on results but on volume. So you would pay yourself a % of every buyin you play rather than on the results, the % would vary depending on game type.
Examples I have seen include:
- Heads UP SNG - 1%
- Single Table SNG - 3%
- 18-90man STTs - 4-7%
- MTTs - 8%
I haven't tried this myself as I am still a casual recreational player, however if I was looking to make regular withdrawals and had an adequate bankroll I would follow a similar cash-out strategy to this. Obviously if you have a big win you can still withdraw a chunk of it but at least you can work out your bills/outgoings and then know what volume you need to put in to atleast cover those... regardless of your results.
Good luck if you do decide to make the move to going pro