Must I complete an orbit before touchdown?

[MajorMushroom]

I've always been circularising a nice orbit around the target planet/moon before landing, but I don't exactly know why. There is bound to be a reason why I can't just set up a collision course, and then just slow down enough. What is this reason? All I can think of is you can pick your landing spot. 

[Cadet_BNSF]

Beyond picking your landing location more easily, no there really isn't much reason too, though I think it might save some DeltaV. However, on tidally locked bodies like the Mun, I am not sure if you could land on the opposite side without orbiting. Someone should probably fact check me on that though.

[linuxgurugamer]

Technically, there is no reason.  To land on the far side, you would have a descending path which curves around the planet.

However, realistically, going into orbit allows you to do a better job of picking your landing zone, and doesn't really cost that much more dV

[MajorMushroom]

3 minutes ago, linuxgurugamer said:

Technically, there is no reason.  To land on the far side, you would have a descending path which curves around the planet.

However, realistically, going into orbit allows you to do a better job of picking your landing zone, and doesn't really cost that much more dV

I see, but let's say I was coming home to Kerbin, low on fuel, could I just collide and pray the heat shields would save me? I think that  creating an orbit would slow you down a bit, but I'm not sure about this.

[linuxgurugamer]

Well, that's a bit different.

So you adjust your path to dip into the Kerbin atmosphere, to a Pe of about 35-45km.  Make the adjustments as soon as possible, so you need as little fuel as possible to make the adjustment.  Depending on the craft and heat shields, you may be ok