For me, it's not so much saving or spending as it is just maximizing your personal utility. I think everyone has their own level of what really matters and what's comfortable to them, but the whole point of frugality for me is asking a few questions:
1.What am I buying?
2. Why am I buying this, really? What do I hope to get out of it?
3. What am I really paying for this relative to how much I'm using this? (per month, per use)
4.What alternatives could get me what I want? What would they cost? How would they be different or less fulfilling?
5. Could I think of something better to spend the money I'd save that would be more enjoyable?
6. Do I still want to buy this, go with the alternative or forego it altogether?
7. If I do want to buy this and think I'll be buying it often enough, is there a cheaper way of getting it (taking into account time costs)?
It's not a "oh-poo-poo your lifestyle is awful live in a shack in the woods" type of a deal. I just think if people stopped more often to consider why they spend what they do, they'd figure out it's more often due to norms or consumerism than any really rational desire. If you go through this calculus and decide it's really the best way to spend your money, there shouldn't be any reason to feel guilty about it.
Example: Do I ditch cable TV?
Well, 2. I want something that will entertain me. I want something that will amuse me and let me see my favorite shows and sports.
3. It's about $1000/year for am HD package that covers the channels I like after fees and taxes come into play. There are about 4 half-hour shows I regularly follow, total programming time without commercials is about 5.5 hours a month. Huh, that's like $15 an hour of programming. Wow.
4.Well hell, for $15 an hour, I could see a new movie in theaters for a third of that! Oh and hey, 2 of those shows are already available streaming, online, with near zero commercials, whenever I want them...for free. The other 2 have all but the most recent episodes on Netflix streaming. Hmm and Netflix would let me watch thousands of movies instantly for $8 a month.
5. Uhm, yes, I can think of more awesome things to do with $900. I could get a home theater system, a netbook, pay for a gym membership, get dance lessons, etc etc.
6. Well I do want SOMETHING with on demand entertainment, but not cable, so yeah Netflix should be nice.
7. Oh I can start Netflix with a free trial and put it on a 2% back credit card. Nice.
Since it's based on your values, I think it's one that really should never leave you guilty, only that your values aren't what you thought they were. Ok so you want a new $60,000 Lexus? Is it $55,000 (lost interest, tax, title, delivery fee, insurance) BETTER for you to have a new Lexus than one than a 10 year old Lexus from a private party? Is there really no other way you could think of spending that money that would make you happier? Exotic vacations, meals prepared by private chefs, your whole house cleaned weekly, flowers delivered to your significant other, a personal trainer, groceries delivered, the fanciest suits money could buy, spa treatments, a virtual secretary to handle all your errands and enough money left over to buy another used Lexus when this one bites the dust? All of those things combined are really worth less to you for something slightly shinier and faster?
It doesn't have to be some unbounded conclusion that makes me renounce all worldly possessions. Do I sell my 12 year old Lexus and bike everywhere? No. Why? I want to be able to drive places, go out of state on a whim. I want to transport other people places and move groceries, packages and other purchases easily between stores and my home. I don't want to be cold driving in the winter, or really be bothered by the rain. I want the convenience and freedom of being able to get up and go whenever I feel like it and move myself a few hundred miles in an afternoon. I don't want to have to carry around a bike lock or a helmet. I don't want to ride on a road or narrow bike lane with enormous, several thousand pound hunks of metal hurdling dangerously close to my vulnerable self. I don't want to have to worry about what type of clothing I'm wearing at night or have to get some silly reflector jacket. These are luxuries that are worth it to me.