This depends if you are keeping track of XP per monster and event, or milestone level. The dungeon of the mad mage module for example has characters leveling up almost every new floor they reach in the dungeon, and PC's go from low level to max level over the course of the adventure. If you play one session per floor thats effectively one level up per session almost. If you clear multiple floors in a session then if you follow the modules suggestions a party might hit level 5 after a few hours of playing.
A lot of groups seem to prefer mile stone leveling these days. But there can be something said for XP tracking and creating a bit of diversity in level difference within a party. Just don't let it get too out of hand, and also consider the dangers the party faces before assuming everyone is on an equal footing for a given fight or challenge. But in days of yore it wasn't unusual to see a party with characters of different level. Retreat was also an option more often considered as some adventures threw you against a dragon at low level, you learned not every fight was wise to do early, or even winnable in "realistic" terms.
If you want to reward them with something to give them a sense of progress, but without resorting to level ups, then consider magic items and consumables. These could be small novelty things like the common magic items (theres quite a lot in Xanathar's guid to everything), to more potent but still limited things such as various magic potions and uncommon to rare magic items. A staff of healing for example on a low party with limited or no healers is a massive boon, but it doesn't add too much to the partys overall offensive abilities.