I have a small smoker, and have never had problems keeping it lit for hours on end. The secret is to use a heat source. When you build a wood fire, there will be charcoals in the ashes when it's cool. Collect those and use a handful when you light the smoker. Put them in a metal flat container, light one with a flame, blow on them until they're red hot, and dump them in the bottom of the smoker.
Pack your smoking material on top. I usually break a bunch of small twigs to help replenish the coals when they burn down, and stuff the top full of dry leaves or grass. Pine needles, wood shavings, pulverized manure, anything that will insulate. Don't try sawdust, it just blows out when you pump the bellows shooting little coals around.
The formula, as any good scout can tell you, is the "fire triangle." Heat, Fuel, Oxygen. The coals supply the heat, the dried fuel material insulates against the coals cooling, and the bellows supply the oxygen. Once the twigs are lit I have no trouble keeping anything actually smoking. In fact, I have to keep moving the smoker to keep the smoke out of my lungs.
Should the inspections last longer than the smoker, I simply open and drop more twigs in, catch them on fire and reload with whatever's handy.