Lewis & Short

as-sŏlĕo (ads-, Ritschl, Fleck., B. and K., Halm, Weissenb.; ass-, Roth), ēre, v. n., to be accustomed or wont (to do, to happen, etc.; only in the 3d person sing. and plur. and impers.): ponite hic quae adsolent (sc. poni), Plaut. Pers. 5, 1, 7; id. Ep. 1, 1, 5: quae adsolent, quaeque oportet Signa esse ad salutem, omnia huic esse video, * Ter. And. 3, 2, 1 (adsolent ergo consuetudinis est; oportet rationis, Don.): cum multa adsoleat veritas praebere vestigia sui, Liv. 40, 54 fin.; 34, 44.
Hence the expression: ut adsolet, as is wont to happen, as is customary, as usual, Cic. Leg. 2, 9, 21: prima classis vocatur, renuntiatur; deinde, ita ut adsolet, suffragia, etc., id. Phil. 2, 33: sacrificio, ut adsolet, rite facto, Liv. 37, 14; 1, 28: ob quem imbrem novemdiale, ut adsolet, sacrum fuit, id. 23, 31 fin.: verbenas coronasque, ut illic assolet, obtulisse, Suet. Vesp. 7: cum in hortis D. Bruti auguris commentandi causā, ut adsolet, venissemus, Cic. Lael. 2, 7: legiones, non laetae, ut adsolet, neque insignibus fulgentes, Tac. A. 1, 24; 3, 1; Suet. Ner. 7, 34.