dispenser and sentry placements

suppose it's a badwater, dust or goldrush map (or any other map design that is choc full of chokepoints and deathtraps) and you are defending with a semi competant team (ie one that piles on the spam with cheese and stickies on top)
Would it be better to move the dispenser as close to the front line as is safe, and build the sentry some distance away from it where it can draw the wrath of ubered demomen and pyros? or is it always better on a pub to use the orthodox approach with building the sentry a good 5-10 seconds further away from your defenders where you can get much more metal at a time to repair?

I've tried a bit of both and I prefer to spread things out a bit when I have a reliable team that forms a battleline around a dispenser when I start building and I also find that amateurs tend to sap anything they see which can be a nice early warning signal at times. Still I'm not certain about how to place everything.

Don't keep your dispenser near the sg unless you are forced to turtle to temporarily cover a portion of the map, or you need the dispenser to jump on to reach a higher point.

I try like mad to hide the dispenser from the other team.  Teles also.

New engy upgrade:  disguises for the buildings!  Oh wait, blazer already thought of this ages ago.

I try to keep one near the front line, because when I'm there, I want one. Its great to put one in a choke point where the enemy cant hit it so you can bang on your SG continuously.

Dispensers now more than ever should not be near your SG, unless needed to lock down an area (which to be frank is rare) and become a turtle-engineer. Ideally, you get a dispenser up somewhere near where your team can beneift from its health and ammo. If your sentry gets destroyed (which is a first target for most during offensive operations), at least your dispenser doesnt go with it. It can still beneift your team.

You basically lengthened what I said