As others have noted, it's called vesting. I hope you and the other founders have vesting contracts between each other as well.
Some countries laws make vesting options a big expense unlike the USA.
How? Vesting doesn't have to be noted in the books immediately, just make a contract which specifies all the details of the vesting without actual transfer of shares, which happens under specific circumstances (e.g. an exit, expiry of the vesting term etc.)
You can use vesting with a cliff
You should probably know that before you start dealing with a prospective employee. If you are hiring quality people then it is definitely worth it. If you don't know for sure then you should not be hiring anyone.
If you think you can know for sure you should not be hiring anyone. Investing in human capital entails risks.
Owning and operating a business does as well. If you don't recruit the best you can for your company then indeed the risk is quite high.