DJ or no DJ

Hiring a DJ will be easier, and definitely have more of a party vibe.

If you do decide to self DJ make sure you have good speakers and that you test everything thoroughly beforehand.

Have all playlists saved to multiple devices in case something goes wrong.

Make your playlists carefully - don't just press shuffle because you won't get a nice flow.

And make sure you lock the device so that no one can change the song. There is nothing worse than random people changing the song 30 seconds in.

You will still need to hire someone to MC and to play the music at the correct times.

I'm hiring a DJ, and more than just playing music and nice speakers and a microphone for the ceremony, having an MC really helps with the flow of the evening! That said, I have been to a wedding that didn't have a DJ and asked a friend to MC—I'd say it went pretty well, but it took them A LOT of time to get everything together themselves, so I'd also take into account how much you think your time is worth.

What does getting married in a church have to do with dancing?

It's been ages since I set foot in a house of worship though, so, who knows...

DJs do more than just play music. They read the crowd, keep things flowing, MC, have the equipment (mics) for toasts, and sound system. Please get a DJ.