Nepal is the destination that made me rethink what "adventure travel" means — this is where the idea for Around The Atlas' Expeditions & High Altitude section actually started. This guide covers the two classic routes (Everest Base Camp and the Annapurna Circuit), realistic daily costs, permits, and the itinerary I'd actually recommend instead of the one every agency sells you.
When to go
The two trekking windows are pre-monsoon (March–May, warmer, rhododendrons in bloom) and post-monsoon (September–November, the clearest mountain views of the year). I've done both — November gave me the single clearest morning I've had at altitude anywhere in the world.
Realistic costs
Budget $30–40/day trekking independently with teahouse lodging and meals, or $50–90/day with a licensed guide and porter — which I'd recommend on Everest Base Camp for both safety and to put money directly into the local economy. Add roughly $30 for the TIMS card and $20–30 for the Sagarmatha or Annapurna Conservation Area permit.
A 16-day Everest Base Camp itinerary
Fly Kathmandu → Lukla, two acclimatization days built in at Namche Bazaar and Dingboche, base camp on day 9, and a faster descent — 16 days total including buffer days for weather, which you should always build in at this altitude.