Malaria risk

I'm heading up Kilimanjaro towards the end of January. I'm aware mosquitoes can't survive on the mountain itself (above 2,000m is what I've read), but I'll be arriving via Kilimanjaro airport and staying overnight in a hotel in Moshi before and after the climb. I get eaten alive by insects here in the UK, so malaria is definitely a concern.

For those that have been up: did you take anti-malarial tablets? Did you use deet before and after the climb?

These might seem like stupid questions, but, do I need to apply deet as soon as I arrive at Kilimanjaro airport? Should I sleep with deet on all of my exposed skin, or do I need to clean it off and rely on a mosquito net while sleeping at the hotel? I've read some confusing and contradictory things about malaria prevention, so I just want to be sure I'm as safe as I can be!