Adding a co-founder may not speed things up, it is just as likley to slow things down, as good co-founders are hard to find. That said the time to do it is when

Adding a co-founder may not speed things up, it is just as likley to slow things down, as good co-founders are hard to find. That said the time to do it is when the rate of progress dropping won't bankrupt you, and you have a chance to recover.