Itineraries: do you use them when you travel? Or do you simply create your own?

Do you use itineraries when you travel? Do you rip out those '48 Hours In...' or '3 Perfect Days in...' pages from travel magazines and newspapers when one catches your eye? Do they end up staying at home lost among your paperwork or do you slip them into your guidebook and take them with you when you go some place? And when you get there, do you actually use them? And what about guidebook itineraries? All travel guidebooks feature them these days; I've just written a bunch myself. They're either organized by duration ("one day in Milan", "weekend at the Lakes" etc) or by theme, with sights and activities suggested by subject or interest, such as "'3 days of food and wine in The Veneto". You get the idea. I'm curious to find out who uses itineraries and how you use them. Or do you simply make up your own? We met a couple of Italian travellers in Australia last year and the woman methodically underlined sights in her guidebook and then wrote out day-to-day itineraries. Her boyfriend was happy for her to do although he didn't seem to mind either way. My interest is partly motivated by comments from readers, in particular Sarah, who in response to my post on casual tourism wrote: "My other half is definitely a casual tourist! Which drives me slightly nuts... I like to plan to ensure I don't miss anything. On our last two holidays, I'm there with the map and the tourist book and he's just like... "can't we just wander around and see where we end up?!" Argh!" I'm interested in hearing from planners like Sarah to find out if you use itineraries and how you use them - what do you do if they're not working for you, say, if you don't like the author's choices, or order of selection, or if there's too much to do on one day? Do you abandon them and create your own? If you're an itinerary user, I'd love to hear from you.