This or even with the bag....depends on situation too....i can't let the ball beat me, so i play up....i've seen people way too deep at 3rd.....how the hell can anyone make that throw?
somewhat agreed with this. playing the ball cleanly is better than playing the ball shallow. just have to play within your abilities and make the best of it.
for coed and lower level i actually usually play deeper. they tend to be slower and the fielders behind me tend to be weaker, so it's a lot more important for me to stop the ball in the infield and i'll still have enough time to make the throw. obviously it will change based on the batter as well.
for men's and competitive stuff, yeah you might as well play in, standing in the grass is going to give them 1st base even if you play it relatively cleanly, so there's no advantage to stopping the ball there vs your left fielder(assuming they have the arm and fielding ability to keep it a single), or you just sorta getting in the way but not being able to make the play because it came too fast. i think it's pretty rare that you miss a catch because you stood too close, just mis-play grounders, or you aren't able to move sideways enough to get in front of it. so playing in almost never cause a catchable ball to be dropped
oh, and use whatever glove size you want. i used to use a 12.75 for the infield and a 14 for the outfield, but once i broke in and got used to the 14 i started using it everywhere and i'm not looking back. learn to play with it and there's no disadvantage. when you need to get the ball out quickly, like with routine grounders, you catch the ball closer to the palm and it's easy to get out. if you aren't able to do that and just snowcone the ball, well then you would have completely missed with a smaller glove anyway. there is no downside