Truly your retirement expenses determine your lifestyle in retirement.. and whether you can afford to keep the same lifestyle is the big question!
If you need help estimating expenses for retirement, go here.
If you lack retirement savings, it's very likely that you need to cut back.. somehow, somewhere.
The biggest lifestyle change might be your home. Some might work hard to payoff the mortgage so that they pay only taxes and utilities (and maintenance, of course) after retirement. Others might downsize to a smaller home, a condo so there is no outdoor work, or an apartment.
I've seen retirees sell a lifelong home, move to an apartment -- and yes, they do pay rent, but they live quite nicely without hardly a care in the world.
Both condos and apartments seem to work well for retirees. You've got neighbors nearby, you have complete privacy, security, and no upkeep or maintenance on the “home” whatsoever! Come and go as you please. Enjoy Life!
Ok, if you think that cutting back is not necessary – do consider that your leisure activities, day trips, lunches out, and travel will all add up. It's hard to know what your expenses will be in retirement. You know what they are now,... but they will change. Even something like air conditioning and heat – if you are home, you'll use more of both, where you could level those out when working.
Finally, don't forget that Health Care expenses are increasing dramatically. If you have great health care, so you believe this doesn't affect you, think again, Many employers are changing the level of retiree health care coverage.