[ISNIT]

I have the exact same issue with my projects, but recently I read something which seems to have helped over the last few weeks;

"Never got to bed satisfied."

It means, don't stay up all night fixing that issue, leave it till the next day when you will really want to start fixing the issue.

It seems to be a great way to maintain focus and motivation.

[Mumm-Ra]

This is great advice.

I recently learnt to say enough is enough when my program won't work and leave it until the morning.

Fresh eyes give me a huge boost some times - and often take the work in a whole new and improved direction.

[ashleyp]

Got a link to that?

[ISNIT]

I did have a look, unfortunately it was one of the many different 'Starting a Start-up' posts.