Day Trip: How much travel time?

I live a couple of hours from Chicago and just a bit farther from St Louis, and we have often done day trips to both. Much more than that would be too far for me to consider as a day trip unless I was on a train (tend to have some vision issues after dark if I have been running around all day).

From Munich, I've made a day trip to Salzburg, about 2 hours one way. Actually, I saw everything I planned (wanted) to see in Salzburg by late afternoon and returned to Munich for a late dinner. I guess a lot depends on how long you need to spend in the town and how important it is to you to see it. I traveled from Fischen im Allgäu (near Oberstdorf) to the Zeppelin Museum in Friedrichshafen (2½ hours each way). I had plenty of time to see the museum, which was the only thing I wanted to see there.

For us, the max would be about two hours each way since four hours of travel would be a significant part of any day. Much prefer closer to an hour or so. Whether to hang around later depends on several factors especially the transportation schedule. We often do but I try NOT to catch the last train/bus. Like to have a back up in case I miss it.

I made a daytrip to Rouen from Paris took 1.5 hrs by train,, I thought it was a great daytrip but do regret not having enough time. I could have stayed longer. I was on my own so did arrange to take an earlier train home ( I think it was about 6.30 or so ). If I had been with someone I would have taken a later train but on my own just thought I would rather be back "home" in Paris earlier.
I did similar when I took a daytrip to Bath( also about an hour and a half)... could have stayed longer but was happy with the amount of time I spent there and the amount of time on the train. I consider 1.5-2 hours a reasonable amount of time to commute on a daytrip if you spent the entire day there.

Thanks, everyone. I asked the last question, about staying into the evening, because a lot of places have a different feel after sunset, when the (other) daytrippers have left, but, not being a nightowl, I also don't like getting back very late at night. That is one reason I am asking about travel time each way.

To me it depends on 1) how much I want to see the place and 2) how early I'm willing to get up to get going there first thing in the morning. My most extreme example was taking a bus from Cancun to Merida (beautiful colonial city on west coast of Yucatan) that took 4 hours each way because I really wanted to see Merida after being in the (ugly resort development) of Cancun. Normally a trip that long wouldn't be worth it to me because the ratio of travel time to on-the-ground time was unfavorable (and I had to get back when the bus was coming back). I think I got up around 6am and got back by 10:30 pm or so. It was a long day but I don't regret it - the two cities were like night and day and that's exactly what I was looking for when I made the long day trip. I have a higher tolerance than most - I could travel up to 4 hours each way on a day trip, be willing to wake up at the crack of dawn, and get back very late...I don't mind coming back really spent, it's usually worth it. On average though, I prefer somewhere around 2 hours travel time - that's ideal. I don't even count 1 hour travel time as a day trip (that sounds more like a work commute). In general, I don't like driving in foreign countries at night but have no problem getting back at night via public transit. A lot of places take on a new life in the evening and it's worthwhile to see that.

My day trips are usually in the 1-2 hour distance range. I rarely stay into the evening because I use public transportation and I do not want to be on the last train or bus back and risk missing it. I would definitely consider staying later if I had a car.

My day trips are usually in the 1-2 hour distance range. I rarely stay into the evening because I use public transportation and I do not want to be on the last train or bus back and risk missing it. I would definitely consider staying later if I had a car.

I'll consider 3 hours (one-way) the upper boundary for a day-trip. But that should be a visit for a site I'm really interested in. Otherwise, 90-120 minutes is the most I'm willing to go (one way). Otherwise, it becomes some transportation vacation day, which might be fine on itself if the road involves scenic course, or other stops - but then it is a different type of day-trip altogether. However, I try not to take too many day trips. They are nice, yet often there are interesting things to do, eat, see on the place I'm already based at. Here on the Helpline I often read plans like "I have 4 full days in Rome, I want to take a half-day trip to Ostia and another to Pompeii and Capri. Are the 2 1/2 days left enough to see the sites in Rome?". Personally, I'm not a big fan of this rushed approach, as in feeling the urge to visit somewhere else close to where I am "just because" I can increase the count of places I set foot on.

Like others have said "it depends". We have done trips where we were on the train for 4- 4 1/2 hours one way- usually that is to sample a destination we are considering for another trip (we did Edinburgh first as a day trip from London for example). When we do the 'long' trips, we usually will stay for an early supper and get back to 'base' rather late (10-11pm). But mostly we do 30 min. -2 hours. London is an example of a great base with lots of wonderful day trips you can easily do by train that are no more than 2 hours away.

If I'm out early in the morning for a day trip, by the time I've crammed in as much sightseeing as possible, I'm too tired to want to hang around and I'm looking forward to the train ride back. If sunset is early, it's often nice to see the place after dark, but "evening when the locals come out" is pretty late in most of Europe. I guess it depends on your energy level and if there is enough to interest you after sights close and before dinner time. You can always sleep on the train back.