People talk about experience as if Arsenal and Tottenham have any in title races, they simply don't. The only history they have is of bottling title races (Arsenal) and top 4 races (Tottenham), neither of them have really proven that they're capable of sustaining pressure and if anything, pressure will be on Arsenal and Spurs to deliver, not Leicester. For Leicester at this point everything is a bonus, they were expected to fight for survival and are now virtually certain of Champions League football next year which is a huge deal. If they win the title, great, if they don't and end up 3rd or 4th - it's still going down as the best season in their history.
Thing with those smaller teams on great runs is that they usually want it more. Arsenal or Spurs may think there's still another year for them to make a run, at Leicester everyone know it's now or never. They're not likely to be in another title race for decades. They will be sure to take one game at the time and treat them all as cup finals, with 12 games to go and other teams bound to drop points they probably know that winning 8 of them will give them the title. The next 4 games are absolutely crucial - Norwich and West Brom at home first, then Watford away and home to Newcastle. In the meantime Arsenal travel to Man Utd and Spurs, Spurs travel to West Ham and host Arsenal, both will drop some points. If after the next 4 games, with 8 games to go, Leicester are 3-5 points ahead of 2nd placed team, they will have a great chance. It's key that they win their next two games and don't look over their shoulders too much.
The final 3 games will be absolutely essential but I'm pretty sure that if they go to Chelsea needing a win they'll get it, especially if they're in the race with Spurs or Arsenal as Chelsea players will relax a bit and won't want to do their local rivals a favor that much. It's still the 9 games that precede that run that will have the biggest impact on the title race and they're home for 5 of them and the away trips they have are usually not the toughest sort. I can realistically see them getting 20-22 points from these 9 games.