Back when I was commuting and had just one bike I had a few situations like this where the tire would loose 10-15 psi on the 9 mile/40 min ride to work. I'd top it off and ride home (9 miles and ~50 minutes...because uphill) and loose about the same. In the morning it'd be almost flat.

If I was slammed at work that week, I might let it go 'till the weekend, or the weekend after that. Later on, when I had more autonomy at work, I could schedule my own breaks, so I'd just patch or replace the inner tube out in the warehouse when I arrived, or after work when I could make time. I could do it at home, but once I got married I wanted to spend time with my wife and family...at least for a few years, then working on the bike became a refuge from chaos.

Still, later, when I had more than one bike, I'd just take another bike.

But I do remember a few slow leaks where I let it go a week or two because I tend to top off my tires before each ride anyway.