Don’t misuse HST/GST collected.
We have worked with several entrepreneurs who get behind in submitting their HST/GST because they have not kept the money separate and used it for something else. In some cases, I have seen their business accounts frozen by CRA. To prevent this, open up an account specifically for the HST/GST remittance. I recommend a business account that has a high daily interest rate and no monthly fees (yes, there is one out there designed specifically for business owners). While the money is sitting there, why not make some money on it?