Difference- Lifeline or Instance

[Tehila1]

Is there difference between adding an instance or a lifeline to sequence diagrams?

Thanks in advance!

[qwerty]

Not really (though EA makes a difference in the appearance in the browser). Both represent instances.  You should choose either to make your models consistent. In the past I just used instances but nowadays I tend to use lifelines instead. Probably because the menu (and the overall situation) was more messy in the past (so the cleaned that at least).

q.