I don't know about other smokers but with my Traeger pellet smoker it is easy to keep a clean area. It does not leak. I foil my drip pan and all the grease runs into a small bucket. I usually clean after every cook in the summer and after 2 or 3 in the winter. I clean my grate with wadded up foil, works better than a brush to me. I clean it right in the smoker so and charred bits fall on the dirty drip pan. I remove the drip pan and just fold up the foil and all the mess and throw away. I remove the heat shield and vacuum out all the ash. My barrel is pretty clean, free of grease. I never cook without the drip pan like some do. In the spring I will scrape all down and it will be good for another year. Some foil their drip bucket but I don't, I just empty before it runs over into a 2 gallon wide mouth plastic jug. When it gets full I take to Sandman's carry out and dump in his large grease bin. I local recycler buys the used grease and oil from him.
One reason I like my pellet smoker is the ease of keeping clean. Smokin Don