Sal's correct. It's a tradeoff, but if your raising from traditional VCs, your can always structure a deal that includes additional traunches of cash if needed. It's fairly common to negotiate an initial investment that preserves your equity and covers what you think you need while making sure your investor will be there if additional capital is needed. Additional investment can be more expensive (i.e. a bridge loan with additional warrants), but you can typically negotiate so you know what your getting into.
This is one of the main reasons you should be seeking VC funding from established investors and know where they are in their investment cycle.