Indeed.Never climb with only spikes and a lanyard. Always have a life line. This will make you more comfortable, give you more positioning options, and also give you a chance to rest your legs and think about what you're doing.
Most importantly, the life line is a much faster descent system and there are a thousand reasons why you would need to get out of a tree quickly.
When you free climb with spikes you're trading safety for time. This might seem like it's worth it at the beginning but as you get better at working with safe techniques, you'll actually find them to be faster and easier.
What I've seen new guys do is when one spur slips panic and lean into the tree trying to bear hug the tree and in return your Spurs naturally angle out away from tree causing now both Spurs to loose contact, so learn to not panic and just keep both Spurs angled into tree, the spur that slipped will bite within a few inches and even if not just transfer wieght into remaining spur and regaff tree withother actually easier than it sounds main idea is to not panic it's instnck to want to bear hug the tree making things much worse!!!When ascending with double wrap lanyard, keep both hands on the tree like holding a women's waist and bring it up(lanyard) as you climb.
I'm kinda new with spur climbing and i find it effective when done this way, well maybe for that particular tree i guess.