Does a boil have to be 60 minutes long?

I'm new to this so bear with me.
I've gotten 2 kits, each from a different retailer - Midwest and More Beer. Both call for 60 min boils, but here's the thing. The Hop additions on both these kits are very late in the boil - in the last 15, 10 and 5 minutes.
This being the case, does the boil have to be so long, unless the extract takes that long to "break" or be conditioned.

Thanks for replies

No need for more than 15 minutes with extract.

If the kit recipe has a bittering addition,then yes,you need to do the whole 60 minute boil. If it's using pre-hopped extract,usually bittering,then you can do a shorter boil for the flavor & aroma additions. But never boil pre-hopped extract for any length of time,as it changes the hop profiles designed into it.

Not to be a smart ass but are you sure you are not confusing the instructions? I'm aware that "all late" hopping is becoming more common, but the norm is a 60 minutes addition for bittering. I'm just wondering if you're seeing a 60 minute addition as being AFTER 60 minutes of boiling. Hopping schedules are backwards from intuitive.. a 5 minute addition is Tminus 5, not 5 minutes into the boil. If you're well aware of this, carry on.

What happens when hops are boiled for more than 60 minutes? 120 minute IPA comes to mind here. Why boil for 2 hours?!

Boiling drives off SMS, which are DMS precursors. Some malts require a longer vigorous boil to make sure all of the unwanteds are gone. Plus, boiling can cause some amount of caramelizing, so that might be desirous.

Then you have the hops to think about. Almost all beers have a 60 minute bittering addition. 60 minutes is the defacto standard for adding bitterness without flavor and aroma. It's possible to add enough bitterness with the late hops additions, like at 20 or 30 minutes, but this is relatively new, and mostly for American Ales like Pale Ale or IPA which are very hop forward.

Some of the popular homebrewers, like some that are found on The Brewing Network podcasts (Like Jamil, Palmer, etc.) tend to boil for 90 minutes, as they think it gives a better beer in the end.

You can do what you want, and there are no hard and fast rules regarding this, but whatever you do you have to live with the consequences for the full 5 gallons. I'd be leery about boiling for less than 60 minutes. That's a lot of beer to drink if it ends up with off flavors or underbittered.

I've done 45 min boils with lighter styled beers where using 1 oz of hops in the whole thing was still a bit much so I reduced the boil to lower the IBU's. It was OK.