I'm just wondering how many points most X-wing tournaments allow for squadron building? What's most common to play at?

Almost always 100 points, unless you are playing escalation. 75 minute rounds are normal.

Our group almost always plays 60 min rounds as practice, as many tournaments are forced to make them 60 min for timing purposes.

Yep, most tournaments I've been a part of have been 60 or 65 minute rounds.

The guidelines in the tournament rules (you can find them in the support section of the X-Wing catalog page) say that standard tournaments should be 100 points with 75 minute (+or - 15 minutes at the TO's discression).

Don't forget it is not just point limit but also the size of the play area.

Standard is 100 point limit on a 3'x3' play area with 3 obstacles (asteroids) per player.

Now it is alright to to alter the numbers such as 150 points with a 4'x4' or 60 points with a 2'6"x2'6". Or you don't even have to keep proportions such as 120 in a 3'x3' or 100 in a 4'x4'. But for tournaments it is best to have a standard all can agree to so people know what to expect. Now if tournaments want to tweak something it must be made clear in advanced but also everyone must accept it will play quite differently from the standard meta.

As above.

But our FLGS, we'll often play 125- or 150-point matches, just to bring more equipment for fun times.

However, if you're wanting to seriously compete, get as many 100-point games in as possible, and as noted sticking around the 60 minute time limit.

Escalation tournaments are usually, 60, 90, 120 and 150 pts with 60 minute rounds on a 3'x3' mat.

Alrighty, ty.

As above.

But our FLGS, we'll often play 125- or 150-point matches, just to bring more equipment for fun times.

However, if you're wanting to seriously compete, get as many 100-point games in as possible, and as noted sticking around the 60 minute time limit.

I forgot time, yes that is important too. Now as a casual usually time doesn't matter as this is just a fun pastime as in it is supposed to adsorb time which may be normally be occupied with boredom. However with time limits in tournaments you may need to tweak lists. As I played Imperial guard it was often that I only got to the 3rd or 4th turn (and felt guilty that those were the games I did good in). However if time is a consideration as it should be in tournaments then how you play a swarm list will be a big factor.

I usually play 100 point games, though this may vary depending on who I play with. Against friends, we might play more or less than 100 points, but we try to make sure that we have builds that roughly the same number of points.

100 points for tournies. But we tend to play 150 as casual games, add a limit of 8 ships per side, then 3x3 is still fine to play on with standard asteroids, and you get to play with the cooler specials too.

Works for us, but YMMV