When you get Ultra balls, at level 20 I think. Use them sparingly! I’m on 22 and have not gotten any more for leveling. You can get a few at stops, but they are hard to come by.
I met a fellow who was on level 28. He told me he never received any from leveling. He did say, at 25 I believe, you get TWO potions that will revive anything back to original health. You only get the TWO of them and he has never seen them at stops. Save them until you really need them.
Chatted with a couple at one park with lots of stops in it. She had incense out and the stops had lures. She was getting much different pokeymon than the rest of us. They were not even on our Nearby screen. Apparently, according to them, the incense attracts different ones to you, for having the incense. They still saw all the others we did also. I have not tried this one so take it for what is worth.
Some stops give out different items on different days. There is only one nearby to us and I go just about every day, throw out a lure and walk the parking lot. Some days you will get a lot of raspberries, some days Great Balls, some day eggs, others potions or revives. If I get a couple great or ultra balls, I’ll hang out a little longer and catch piddgies and rats while waiting for the stop.
We all know different PokeyMon spawn in different areas. We seem to have little but Pidgies, Rattatas, Spearows and Eevees. Our rural location is not a mecca by any means. We can get the occasional different one but nothing too exciting. If you are starting out and have this, catch all you can and save candies for later. As pointed out above, the higher level you are the better your evolves will be. Still trade them in and then evolve what you can, with a lucky egg, to gain XP and level faster. I wait until I can evolve 30 or more before doing it. Count candies and save two extra’s to evolve. If you still have time on the egg you can transfer some and evolve another on your egg. Sometimes you end up with more candies than you have PokeyMon to evolve. For us not an issue, more can be found in the next few days.
Those 10 and 20 CP Pidgies will all but disappear and be replaced by 200 or 300+ ones. I throw regular balls at them. I’m finding sometimes one ball will catch a higher CP one. Sometimes they escape 3 or 4 times before I get them or they run away. I save great and ultra balls for traveling to exciting stops. Regular balls can easily be had, the other ones have to be found at stops.
Clear your storage before going to an exciting park!!! Trade in all you can to leave enough space to fill it again. Same with your items. Clear out what you are not using as you will fill up again pretty fast. We go to one park where we can get three stops at once. In more than one location also. Pretty exciting for us. There are always three lures out at once and we can add one if it is vacant. Nothing worse than sitting, using up battery to transfer a bunch that you should have done at home while plugged in. I will actually trade in all but one of some. Say Pidgies. I may have 112 candies but will clear it out to where I only have one Pidgie. I can catch more at home before evolving and want that space for exciting critters we can’t get here.
Have fun catching!