1.
The hotel is almost always full.
 Hotels that give great value and service will be consistently full.
 A cheap hotel that is hard to get into in the low season is the best sign that they are doing a good job right now! People extend their stays, and people go out of their way to go back.
 If you look hard at these hotels, you will see that they have some magic working for them, be it a great bar, really good food, or the clientele after seeing each other over the years, have developed a rapport with the other guests and the staff, and meld into a loose family away from home.
  2.
The word of mouth is consistently good.
 The big guide books only see the hotels infrequently, and what was a good hotel in the past, might not be any more.
 The great cheap hotels, even as they get older, still have brand loyalty because they are doing the things necessary to keep the user experience high.
The great budget accommodations retain great staff, and gain efficiency, and the process in the background that you don't see, gets honed to the point that the hotels operate on autopilot.
  3.
The staff will take time with you to explain things that don't have to do with the hotel.
 This for me is one of the surest signs that you have a really great cheap hotel, several hotels that I personally highly recommend on a regular basis, display this characteristic and they regularly will go over and beyond to recommend great restaurants, good tours and scams to watch out for.
 This means that the hotel has your best interests at heart, and this behavior always manifests itself in the hotel, they want you to have a great experience with them, so that you will come back, and intuitively understand that it is the total experience, both inside and outside of the hotel that contribute to this.
 The bad hotels can't be bothered, which means that they will not bother on the maintenance, or problem resolution, they see you as an inconvenience, rather that as a opportunity to serve you.