Invited to interview for several postdoc positions - how to proceed? I'm currently in the process of applying for postdoc positions. So far I've applied for four, and to my surprise I've been invited to interview for three of them (1 phone, 1 Skype, 1 face to face) so far (the fourth hasn't got back to me yet).

This is obviously a good position to be in, but it raises some questions for me about my next steps. Until now I've gone with a fairly scattershot approach, on the presumption that the majority would outright turn me down. Now I'm wondering if I should start being more selective in which positions I apply for?

To be clear, I would definitely be happy to take any of the jobs I've applied to so far. But what if 'the perfect job' comes up later, and I'm potentially already committed to making a decision on another job offer? (Note, I would not accept an offer then renege on it). 

Is it still worth applying for many positions, for the interview experience, and potential to get a preferred option?

Also, would it be reasonable for me to be offered a position and then turn it down, or should I try to avoid that situation?
No matter what you do, or how carefully you apply, a better job can always come up later. 

The decision you have to make is not "is this my perfect job?", because unless there's a specific single position that you have your eye on, there's no such thing; it's "is this position good enough that I'd take it if offered?". If it is, then do the interview, and if it goes well (in both directions), choose between the offers that you have available to you at that time.